There was of course the one that got away. A perfect example with everything intact, including the box and receipt, listed for $250 on eBay. In retrospect I should have jumped. I made a best offer that was rejected only to see the PowerBook sold at full price while I hesitated. So the search went on.

PowerBooks with broken hinges. PowerBooks with damaged screens. PowerBooks covered in bumper stickers. PowerBooks that were clearly not the model the eBayers thought they were. And PowerBooks that looked like their last job was at Blendtec.

What does a man have to do to get a 12 year old computer any way?

And there it was, listed on eBay by a recycling center. No AC adapter, a nearly dead original battery, a dead Superdrive, and only 512MB of RAM. But otherwise in good physical condition, save a few scratches and scruffs, for a mere $50 and cheap shipping.

I was like a kid waiting for Christmas before that PowerBook arrived.

First Impressions

With the exception of the first Mac Portable Apple has generally been a step ahead of PC notebook manufacturers. The first PowerBook trio offered great screens, quality trackballs, and a keyboard forward design that would become standard in the world of notebooks. The Duos had docks that turned ultra light notebooks into full fledged desktop Macs with extra RAM, additional drives, and NuBus cards. Later on Apple would shave weight, explore new materials, and evolve their designs to the industry leading MacBooks we have today.

Unpacking the TiBook I could immediately appreciate both the quality of the design and the improvements Apple has made since then. The Titanium case feels very sturdy, much more so than plastic PC notebooks, but still not as solid as today’s unibody aluminum MacBooks. It’s thin and light as far as notebooks of the time period go, but heavy compared to Apple’s latest. The latching mechanism is cool if a bit delicate compared to the magnets used today. The keyboard is great. But the trackpad…the trackpad leaves a lot to be desired. Every tap click is a ‘thunk’ and this is perhaps my one major disappointment in this model. It feels like a step back from the trackpad in a PowerBook PDQ, and pales in comparison to Apple’s best-of-class track pads today.

Track pad aside, this would have been the notebook to have in 2002.

As for my specific TiBook, the only real disappointment is that the screen has a line of light scruffs across the middle. Not too distracting. But you just cringe when you realize someone stored something between the screen and keyboard, and whatever it was had a surface rough enough to scruff the screen. What are people thinking when they do stuff like this? It’s just annoying enough that I might take on the task of replacing the screen with another one off eBay.

I can’t complain for $50. RAM is cheap, a new Superdrive is cheap, and the only thing that scares me about the screen is the possible work involved replacing it should I decide to.

Initial Upgrades

I didn’t order RAM when I ordered the TiBook (should have), but I did have a spare 64GB KingSpec PATA SSD on hand. At one point I tried putting this in my PowerBook PDQ, but that PowerBook wasn’t happy with it for some strange reason.

That’s OK because the TiBook loves it. I prepared the drive on another Mac with Mac OS X Tiger and the Mac OS 9.2.2 System Folder that the TiBook requires, and then installed it.

Mac OS Classic Never Felt So Good

Having spent a lot of time recently restoring and playing with older classic Macs I wasn’t prepared for what a TiBook on a SSD would feel like. With some caveats this machine feels as snappy and fast running Mac OS 9 as my MacBook Pro feels running Mac OS X.

Sometimes faster. Office 2001 launches instantly where the latest and greatest takes 3-4s on a MBP. The apps themselves also feel snappier in use. (Come on Microsoft! I realize later software has more features. But given the vast difference in hardware your latest version really shouldn’t lose this race.)

To Adobe’s credit their latest version of Photoshop on a MBP launches a bit faster than Photoshop 7 on the TiBook. And of course image processing is something that’s going to exercise the CPU hard, meaning a 1 GHz G4 has no chance in a race against a Core i7. Still, Photoshop 7 is very responsive, and editing an image on the TiBook isn’t terrible unless you try working with larger files.

The web? Classilla, which was a disappointment to me on the older 60x Power Macs and even the PowerBook PDQ, runs very well on the TiBook. So does TenFourFox when booting Mac OS X. To be clear, rendering web pages is another area where the shear CPU and memory speed of a modern computer means the TiBook has no shot at winning. By comparison to a Core 2 Duo or higher the web is sluggish. But not painfully so like on the PDQ. Flash apps aside, you could actually spend the day web browsing on a TiBook and TenFourFox.

Heck, a student on a tight budget could do real work on this machine.

Part of this is no doubt thanks to the SSD. I didn’t spend much time using the TiBook with the HDD. But from what I did see the SSD made a large difference in performance despite the limitations of the IDE interface. Suffice it to say I never experienced speed like this back when Mac OS 9 was current. My fastest OS 9 machines back in the day were the Power Mac G3 and a 333 MHz Blue iMac. When I moved to a G4 I moved to OS X and never looked back until now.

Those Caveats

So when does the TiBook not feel fast and responsive like a modern computer?

I’ve already mentioned the obvious case: when the task at hand really exercises modern hardware. The smaller apps and lighter OS mean that the G4+SSD can feel as fast as a modern computer for lightweight stuff. But it’s really not and that shows with heavy processing.

The other caveat is that there is a single processor in the TiBook, and Mac OS 9 has cooperative multitasking. So there are hiccups and pauses of the kind which have been nearly eliminated with multiple cores and preemptive multitasking. You can be humming along and get a watch cursor for a few seconds for no apparent reason other than some programmer in the past did not yield enough time back to the OS. You almost never see this on a modern Mac, even when running Windows in a virtual machine at the same time. On a modern Mac a single program may give you the beach ball, but everything else remains very responsive.

Should You Buy One?

If you’re interested in running Mac OS 9 and old Macintosh applications then the 867 MHz and 1 GHz G4 TiBooks are two of the computers I recommend. Max out their RAM, drop in a SSD, and you will be hard pressed to find a faster way to run OS 9 apart from emulation. SheepShaver is good but has its own challenges and compatibility issues.

Another option would be a G4 tower. A dual G4 Power Macintosh scores higher on GeekBench but only because the score includes both processors. Very few classic applications can take advantage of more than one processor or core. The PowerBooks are a lot smaller, lighter, and quieter. Nothing against the G4 towers if you have the space and want one, but for most people playing around with old apps I think a PowerBook is just more convenient. Plus it can serve double duty as a second gaming machine or web browser on a trip. Granted that may seem silly at a time when every kid has a tablet, but in the TiBook’s defense it has a real keyboard.

Is a SSD Worth It?

If you’re going to spend any significant time on a classic Mac I think the G4 Macs are at the level where a SSD is worth it.

I would probably recommend an OWC Legacy Pro SSD over a KingSpec. They are over provisioned and the SandForce controller is better at wear leveling and maintaining write speeds over time. But as you can tell from my review the KingSpec SSDs are not bad at all, and they’re a lot cheaper. I can certainly recommend them as well.

Keep in mind that all SSDs will eventually lose their data if powered off for a long enough period of time. That period of time will vary based on the drive model and storage conditions. For this reason I backup and archive all of my SSDs to external HDDs.

For the record, I was indeed the one who edited that page. After publishing The Mythical Road Apple I edited the x200 related pages on Wikipedia to remove inaccurate motherboard information; add accurate text about the same; and replace Low End Mac’s links with a link to Apple’s technical note at the original location where I found it.

With that out of the way I’ll take a moment to respond to the post by ClassicHasClass.

A Tale of Two Computers

One thing which may have gotten lost in all the technical detail of my article is that 603 based x200 Macs and 603e based x200 Macs behaved like completely different machines. Invariably when you read end user complaints about the x200 series the complaints are about a 603 based model.

The Low End Mac articles treat all of the models the same and attribute any issues to the motherboard. Discrepancies which were reported by readers back then, such as good performance with later models or higher than 9,600 baud serial port speeds, were hand waved as improvements to Mac OS.

Naturally ClassicHasClass does not make any of the technical errors that Low End Mac makes in their articles. The guy knows his stuff. And his technical critiques of the motherboard are valid. While the motherboard was nothing like the descriptions at Low End Mac, it was indeed ‘less than ideal.’ A board for a 68K processor evolved to host a PowerPC.

The problem is he places too much emphasis on the motherboard. At the end of the day it didn’t make much difference in the performance of the 603e based models versus contemporary Power Macs. And that forces us to the conclusion that it was not the motherboard which hampered 603 based models, but the 603 itself.

Among other old Macs I have both a fully restored 6300 and a fully restored 6100/66 DOS with the 256K L2 cache card. The Power Mac 6100 has a 64-bit path to main memory and extensive DMA support, yet it’s neither faster nor more responsive. The Performa 6300 achieves higher networking speeds even with System 7.5. The 6300 and 6100 are responsive under the same circumstances, sluggish under the same circumstances, and they freeze under the same circumstances. When sluggish or frozen the 6300 just finishes its tasks and becomes responsive again in less time.

The thing that ClassicHasClass spends a good deal of time discussing, controller DMA, was no panacea for Mac OS classic’s cooperative multitasking. Likewise, if a 6300 and 6100 have comparable responsiveness under load but a 6200 is worse, then the difference is not due to DMA.

The Long List of Faults

I was surprised to see ClassicHasClass link to Dan Knight’s Power Mac and Performa x200, Road Apples. Mr. Knight’s article was a rehash of Mr. Barber’s flawed piece. The Mythical Road Apple was intended to completely debunk both. There is not a single factual claim in Mr. Knight’s entire article, with the possible exception of certain comm and PDS cards disabling a corresponding serial port.

I realize that last paragraph might seem harsh. I want to be clear that I have the utmost respect for Mr. Knight, the web site he runs, and the many informative articles he has published. (Likewise for ClassicHasClass and the TenFourFox project.) Low End Mac has been an invaluable resource to the Apple community for years. But Mr. Barber got some bizarre misinformation about the x200 line back in the day, and that misinformation propagated throughout Low End Mac discussions about the machines.

The Speed Penalty

“A 20-25% speed penalty (his numbers), however, is not trivial and I think he underestimates how this would have made the machines feel comparatively in practice even on native code.”

The 6300 feels very much like an 8100/80 and is noticeably faster than a 6100/66. It’s fair to point out that the Performa 6300 has a 100 MHz processor yet feels like a Power Mac with an 80 MHz processor. Clearly the less than optimal motherboard design prevents the 603e from reaching its full potential. Never the less it does not feel slow for computers of that time period.

It was a consumer machine sold at a consumer price. For half the price of an 8100/80 the consumer got a machine with comparable performance along with monitor, keyboard, mouse, and software. If Apple had to recycle the 630 motherboard to make that price/performance point happen then it was worth it.

DMA Support

“His article claims that both the SCSI bus and the serial ports have DMA, but I don’t see this anywhere in the developer notes (and at least one source contradicts him).”

To the best of my knowledge the chips being used supported DMA. But Apple did not always make use of available hardware support for DMA. And it appears from ClassicHasClass’s source that they did not in this case.

“Although Daniel states that relaying traffic for an Ethernet card ‘would not have impacted Internet handling’ based on his estimates of actual bandwidth, the real rate limiting step here is how quickly the CPU, and by extension the OS, can service the controller.”

This is true. But given the clock speed and performance of the PowerPC 603/603e servicing the controller would only be an issue under an extreme processor load. Otherwise 10 Mbps would be child’s play for these processors. Even with DMA an extreme load would affect throughput given the cooperative multitasking of Mac OS. Whatever scenario you wish to set up the ultimate problem is software, and DMA only gives you a little bit more wiggle room before throughput falls due to irregular task switching and limited interrupt handling. This is one of those places where I agree with ClassicHasClass’s critique, but disagree in regard to how much it matters in the grand scheme of things.

Again I’ll point out that the 6300 is not slower than comparable Power Macs when it comes to networking or the Internet. Even when running System 7.5 with MacTCP my 6300 downloads data faster than my 6100. Therefore Mr. Barber’s assertion that the x200 line had terrible performance in these areas due to lack of DMA for Ethernet and serial port transfers cannot be true. If the 6200 was slow on the Internet…and I imagine it was…it was due to L1 cache thrashing by the 68K emulator while different parts of the OS, some PowerPC and some 68K, had to be executed over and over with each data transfer.

Fewer Problems?

“Compare this design with the 9500’s full PCI bus, 64-bit interface and hardware assist: even though the 9500 was positioned at a very different market segment, and the weak 603 implementation is no comparison to the 604, that doesn’t absolve the 6200 of its other deficiencies and the 9500 ran the same operating system with considerably fewer problems…”

The issue I have with this comparison is that Power Macs with processors comparable to 5300/6300 Performas did not run Mac OS classic with considerably fewer problems. They ran it about the same despite having 64-bit buses to main memory and full DMA support. This points to faster CPUs being the main reason why later models experienced smoother operation. It may also point to improvements made when Apple moved from NuBus to a PCI architecture.

Stand By Your Performa

While I agree with many of ClassicHasClass’s points, I stand by my original assessment that the 603e based Performas were good consumer machines for the time. He is absolutely correct in his assessment that the motherboard was not the best it could be. But the price was also not the worst it could be. And while this resulted in a slower machine than otherwise could of been, it did not result in a slow machine relative to the Mac lineup of the time.

Likewise, I still say the performance issues with the 603 based models would have been almost entirely due to the 16KB L1 cache. The 603e models ran fine and there’s no other relevant physical difference between the two.

Upon hearing those words I knew I was in trouble.

I was in a small electronics thrift store, part of a local recycling center that tries to sell whatever will still power on. I was there to pickup a Macintosh LC II advertised for $20. Normally LC II’s go for a bit more, but they did not have the monitor adapters, keyboards, or mice required to see if the unit worked beyond the startup chime.

I was about to walk out with more than just an LC II.

The salesman brought out two Macs: a Power Mac G5 which I will cover in a later post, and a Power Macintosh 6100/66 DOS. Naturally the G5 could use a DVI monitor and USB keyboard so he showed me that it was in working condition. The 6100 was in the same spot as the LC II: all I knew was that it had a happy startup chime.

I pulled off the 6100 cover and found that the hard drive was gone. But the CD, floppy, RAM, L2 cache, and DOS card were all there.

I made an offer on all three, and walked out thinking “where am I going to put this stuff?”

Rest in Peace

The LC II turned out to be a bust. While it had the happy Mac chime in the store, at home it would alternate between happy chime, sad chime, and an angry machine gun sound as if to warn me against disturbing dead computers. The ADB port wouldn’t work even when the Mac managed to boot from a floppy. The hard drive appeared dead, but then worked fine when I attached it to another Mac with an older SCSI port.

I pulled the 80MB SCSI drive and sent this one back to the recycling center.

Two Out of Three Ain’t Bad

The other two worked fine. I had an old 350MB SCSI drive to put in the 6100 so I went to work on it first.

• I took the 16MB DIMM leftover from my 6300CD upgrade and installed it in the DOS card.
• I installed System 7.5 from a CD.
• The CD did not have the components for the DOS card, so I downloaded and installed the software from Mac GUI.

Without the special cable that lets you switch between Mac and DOS modes there was no good way to test the card. The PC Setup software reported that it was working, but I was done until I could hit eBay and Fry’s for more upgrades. Which I of course did the next day.

• Fry’s sells a 3.6 volt lithium battery that works as a PRAM battery replacement in many Macs, so that came first.
• I got the cable I needed with a couple days thanks to a great eBayer.
• With the cable I could confirm that the DOS card worked, so I downloaded DOS 6.22 and Windows 3.1 from the web and installed both.
• I got another VGA monitor adapter so that I wouldn’t have to share the one on my 6300.
• Next up was a Farallon 10baseT Ethernet transceiver.
• Finally I received and installed two 128MB SIMMs for a total of 264MB of RAM (8MB is on the board). You can actually have up to 520MB of RAM in a 6100, but 256MB SIMMs are rather rare and expensive even today.

6100/66 Test Drive

Much like the 6300, the 6100 is surprisingly usable given the age of the equipment. System 7.5 is fairly quick. Office type applications run well. But anything Internet related ranges from unusably slow to literally unusable. Some sites are still accessible if you’re willing to wait and suffer a less than perfect rendering, but this is not a machine you can use to browse the modern web.

DOS and Windows 3.1 seem to run well enough. Apple’s implementation, which allows you to switch screens based on a hot key and share peripherals like the floppy drive, works flawlessly.

File Sharing

It’s interesting to try and get these networked Macs to see each other via AFP.

• My modern MacBook Pro can share files with and remote control the G5 tower.
• The PowerBook PDQ can mount shares from the G5 tower.
• The 6300 OS 9 partition can access the personal file sharing folder on the G5. But it cannot access any other folders that are shared.
• The 6100 on System 7.5 can’t see anything from the G5, but can see shared folders on the PDQ.

Basically the PowerBook PDQ is acting like a bridge for the 6100. I can download something from Macintosh Garden or Mac GUI on the G5; grab it on the PDQ and move it to a specific folder; then download it from the PDQ to the 6100.

Should You Get One?

Much like with the 6300, if you want to run classic Macintosh games and applications your best bet is to pickup a G4 PowerBook, iMac, or tower that is capable of booting OS 9. If you just want to run classic apps then a G5 with Tiger will be even faster, but beware that compatibility is not 100%, especially with games.

Modern virtual machines will run a lot of old Windows stuff including Windows 3.1, so if that’s your interest you may not even need an old computer, much less an old Mac with a DOS card. SheepShaver isn’t as polished as the commercial PC emulators, but it may satisfy your curiosity if you want to play with Macintosh abandonware.

Still the 6100/66 DOS holds a unique place in Macintosh history as one of the few classic Macs Apple shipped with a literal Windows PC inside. Macs today use Intel processors which means virtual machines can run Windows at full speed. And the Mac is so popular with so many applications that few of us even need Windows.

But back then there was a lot of software which was PC only. Niche categories had few or no comparable offerings on the Mac. There was SoftWindows, but it had to emulate an x86 processor. While impressive it was quite slow compared to a real PC. And it couldn’t run some software at all.

If you’re nostalgic for one of these machines you can still find them cheap online. The only problem is that they use what are now rare 50 pin SCSI hard drives. If you’re going to restore and play with a SCSI drive Mac from this era or earlier, make sure the unit you buy comes with a big enough drive. Another option is the SCSI-2-SD card. I’m looking to add one to this 6100 and will post a review once I do.

The next time I went for a visit I asked her about it. And I found it right where she said it was, sitting in a dusty box along with the keyboard, mouse, DB15 to VGA adapter, and a Supra 56k modem.

I grabbed it, brought it home, and carefully cleaned it inside and out. I didn’t think that it would start up. I figured either a component would be damaged by age or that the hard drive would be useless. But when I plugged it in it came right back to life, booting Mac OS 8 and starting up EarthLink dialer and Claris Emailer.

15+ years have passed since that Mac got tossed aside yet it started up like it was yesterday. If only everything was this reliable.

Restoring a Classic Macintosh

So what does a computer nerd think about when confronted with a digital antique?

Upgrades.

First thing I did was replace the PRAM battery with a 4.5v AAA case made by eBayer polaroid_pict and sold at his 68K Mac Store. I highly recommend this case for Macs that used the Rayovac 4.5 volt battery. If you do buy one of these be sure to use lithium AAA batteries or low self discharge rechargeable batteries like those sold under the Eneloop brand. You don’t want alkaline batteries to leak like a faucet, especially if the Mac gets stored away again.

Second was installing a Farallon LC PDS Ethernet card. I got this from the 68K Mac Store as well. These Ethernet cards work great so long as you manually configure them. (The DHCP implementation is too old for modern routers.)

Third was upgrading the RAM. It already had 48MB (32MB+16MB) from a previous upgrade in the 90’s, but now it’s maxed out thanks to a second 32MB 72-pin SIMM from eBay. If you ever upgrade the RAM on one of these Macs see my note on installation below.

I also tried a 128MB SIMM just to see what would happen, but this particular model is limited to addressing 64MB of RAM no matter what you put in. In fact larger SIMMs will cause problems. The 6300 would boot with the 128MB SIMM but immediately experienced problems with screen redraws and soon crashed.

Finally I replaced the 1.2GB drive with a spare 40GB Maxtor drive. I partitioned it as follows:

• 1GB Macintosh HD 91 – HFS+ for running Mac OS 9.1.
• 2GB Macintosh HD 75 – HFS for running the original System 7.5 that came with this Performa. I gave this partition a little more space because System 7 cannot access HFS+ partitions.
• 1GB Macintosh HD 81 – HFS+ for running Mac OS 8.1.
• 1GB Macintosh HD 86 – HFS+ for running Mac OS 8.6.
• 35GB Mac Drive – HFS+ for storing everything that does not need to run on System 7.

You’ll note that all of the OS partitions are safely within the 8GB limit for the IDE controller on this generation of Mac. Also: I have not personally tested all of the disc images linked above. I actually still have old CDs with most of these versions of Mac OS.

None of the PDS video cards seem all that interesting for a Power Mac, so I doubt there will be any more upgrades unless I decide to grab an old TV card.

Getting The RAM To Fit

SIMMs with memory chips on both sides barely fit inside the 6300CD. I assume this would be true for the Performa 6320, any of the 6200 variants, and likely the 5200/5300 models as well. You have to remove the heat sink in order to install the 2nd SIMM. But the SIMM will clear the heat sink once installed.

Never run the computer without the heat sink, even just to test the new RAM. When you reinstall the heat sink you need to clean off the old thermal paste and replace it with a similar amount of paste. I generally use Arctic Silver. The original paste was in a nice circle in the center of the CPU. You don’t have to have a perfect circle, just a small amount of paste covering the same area. My 16MB module only had chips on one side so I didn’t run into this back in the day. But I’m not sure if there are any 32MB modules available like that now, or how rare and costly they might be.

6300CD Test Drive

So how does an old Power Mac compare to modern machines?

Surprisingly well if you ignore the web. The Mac OS 9 Finder feels a bit sluggish but is definitely usable. Mac OS 8.x feels fine and System 7.5 is actually rather fast. Messing around with old apps I was pleasantly surprised at just how responsive the 6300 felt on any of the four OS partitions. The OS and office type applications feel perfectly usable even by today’s standards.

As I said in my rebuttal to the Road Apple articles, I do not recall this being a bad or slow computer. My impression back then was that it was a bit quicker than a 6100/60 with the L2 cache card, and about the same as an 8100/80, two Power Macs I spent significant time on. Which is consistent with its MacBench scores. I was very pleased with this Mac during the time that I used it. Playing around with it today only reinforces my impression of where it stands in Apple history.

Of course any modern machine races ahead with demanding tasks. Editing a 1920×1080 image in Photoshop is slower than editing DSLR photos on a current Mac. Network transfers are severely limited by the 10 Mbps Ethernet. And multimedia CDs are laughably primitive by the standards of the modern web. The programs that do run comparably well are lacking features that today’s user takes for granted, such as sophisticated auto complete.

Yet I can’t help but be impressed with how well a lot of every day office type applications run, as well as some of the programming tools and compilers.

Surfing The Web

So what is the web like on a Mac this old? Better than on a Mac Plus even if getting the web running on a Plus is infinitely cooler.

Classilla will run on a 6300, just not very well. It takes forever to launch, respond to commands, and download/render pages. I get the feeling it’s just not made for this class of machine and may work better on G3 and higher Macs with a lot more RAM.

Internet Explorer 5 runs much better but suffers from a now antiquated web engine. It has no hope of correctly rendering or even reaching most modern sites. JavaScript errors generally cause crashes, sometimes a system wide crash, so JavaScript is better left turned off. With scripting off it does an admirable job considering its age, at least on the sites it can reach.

Netscape Communicator feels about the same as IE5. But it can reach more sites and it downloads files faster. Another plus is that the JavaScript engine doesn’t crash like the one in IE5 so you can leave it on. It can’t run a lot of modern code, but it can at least run some. If you’re going to try browsing the web on an old Power Mac I think this might be your browser.

In all cases I gave the test browser as much RAM as I could.

To be clear the 6300 is not usable as a daily web browser. Browsing the web with a machine from this era is purely for the challenge. One of those things you do just to see if it can be done. 20 years have gone by since this Mac was released which is an eternity for Moore’s Law. It’s hard to overstate just how powerful our computers are today by comparison. The fact that a computer with 64 MB of RAM and a 100 MHz 603e can access and render any of today’s web is impressive.

Should You Get One?

If you’re interested in running classic Mac OS and old applications you could certainly do worse than a 6300. That said, you can also do better.

If you happen to have any of the early Power Macs, or run into one for next to nothing, don’t throw it away. At the very least clean it up, verify that it works, and sell it to someone who wants it. Even if it doesn’t work the parts can help keep another Power Mac running, so keep it away from the recycle center if possible.

But if you have a little cash to spend and are interested in classic Mac OS you can easily get a G4 PowerBook, iMac, or tower. (Note that G4 Macs later then these models cannot boot OS 9.) These often go for $100-$150 and, sometimes just $50. They can also dual boot into Mac OS X which gives you access to newer applications.

If you don’t care about running Mac OS 9 directly but do care about classic apps then a Power Mac G5 or iMac G5 may be a better bet. Mac OS 10.4.11 Tiger was the last release to support the classic layer. Compatibility in the classic layer is almost as good as running OS 9 directly, games being one notable exception, and a G5 is faster than any G4 Mac. Thanks to TenFourFox these machines are still usable on the modern web.

There’s also emulation to consider. SheepShaver is particular good at running a wide range of old Macintosh software, though it struggles with some games much like the OS X classic layer. There’s even a Mac Plus emulator written in JavaScript and one which runs on a wrist watch.

Of course nostalgia need not obey reason. If you have fond memories of this machine, or want to see what this era of Power Mac was like, by all means pick one up. You can still find them on eBay from time to time or on your local Craigslist.

The article portrays this series in a rather poor light claiming that it was “…horribly crippled by an incredibly bizarre architecture…” I was surprised to read this. In the 1990’s I used a Performa 6300CD for a couple of years and I never thought of it as being a bad or slow computer. Curious as to how this line got such a poor reputation I followed the links to read both Power Mac and Performa x200, Road Apples by Dan Knight, and Performa and Power Mac x200 Issues by Scott L. Barber.

I was immersed in Macintosh programming in the late 1990’s and I’m familiar with both the PowerPC architecture and Apple’s motherboard designs. I don’t know what the source of information was behind these articles. But just about everything they say is wrong.

Some of it is bang-your-head-on-the-keyboard wrong.

I think Low End Mac is a great resource and I intend no disrespect towards the authors above. But these articles are a source of myth and confusion about the x200 series. In this rebuttal I will focus on and quote Mr. Barber’s piece which appears to be the foundation for later articles.

Addendum: Ted Hodges followed up to my article with a new article at Low End Mac: The Golden Road Apple: How I Discovered that the Worst Mac Ever Wasn’t.

While there are other links below the most important references are:

• IBM’s PowerPC 603 RISC Microprocessor Technical Summary
• IBM’s PowerPC 603e RISC Microprocessor Technical Summary
• Apple’s Developer Note Power Macintosh 5200/75 and Power Macintosh 6200/75 Computers

Background

The first x200 models used the PowerPC 603 processor which had a 16K on-chip cache (8K data + 8K instruction). This cache was too small for Apple’s 68K emulator to work efficiently. Even PowerPC native apps were affected because large portions of the OS were still 68K. This was not the case with the 603e used by later models as it had a 32K on-chip cache (16K+16K).

Other than the cache difference, everything I say below in reference to the 603 applies to the 603e as well.

Memory Bottleneck

“What this means to the home user is simple: Because the memory path is only 32 bits wide and the processor uses 64-bit commands, it takes four processor cycles before an instruction can be completely sent to the processor.”

The 603 implemented the 32-bit PowerPC architecture. Instructions, addresses, and general purpose registers were 32-bit and could be loaded with a single read over a 32-bit bus. The floating point registers could be treated as 32-bit single precision or 64-bit double precision values.

Put simply, the 603 did not need additional cycles to load a command on a 32-bit bus and therefore did not take “…four times longer to process anything.”

What about 64-bit values? The 603 was a superscalar processor with an independent Load Store Unit (LSU). This means the other units could work on data in the registers while the LSU accessed main memory. Loading a 64-bit value would take more time over a 32-bit bus. But it would neither pause the 603 nor require extra cycles to compose the value. As such the load times given in both articles were incorrect. (DRAM access timing is beyond the scope of this article. I will likely address load times in a later article.)

The LSU was not limited to floating point values in 8-byte transfers. It could move two instructions or integer values. It could also perform 32-byte burst transfers. These involved multiple data bus accesses but were streamlined in other ways. So while Mr. Barber’s specific claims are false, the general claim that a 603 would be faster on a 64-bit bus is true.

How much faster would depend in large part on the presence and speed of an L2 cache. Without one the difference would be somewhat less than 2x due to DRAM latency. But with a cache the difference would be much smaller.

The x200 models had a 256K L2 cache on a 64-bit bus clocked at processor speed (please see the 40 MHz addendum under x200 Motherboard). Because of this the impact of the 32-bit memory path was minimal.

Evaluating the 32-bit Memory Path

The standard benchmarking tool of the time, MacBench, used real world algorithms which included a good mix of memory I/O. The tests were affected by data buses and caches like any real program. MacBench scores should therefore give us both a reliable indication of overall performance and a way to estimate the impact of the bus.

These three Macs are very close in processor, memory, and bus speed, and they all have a 256K L2 cache. The 603e integer unit was a little faster than the 601 integer unit. But this is about as close as we can get to equalizing other factors given the equipment Apple shipped.

As you can see the 6300 score falls shy of the 7500/100 by about 20% and is very close to an 8100/80. While specific algorithms might see more or less of an impact, I think it’s fair to say that the overall speed penalty of the 32-bit bus was roughly 20-25% versus 601 based Macs. This is a far cry from 4x or even 2x.

Mr. Barber claimed that these Macs scored well on benchmarks yet were “absolutely terrible” in the real world. This may have been true with 603 based models due to the emulation issue. But there’s no reason to doubt their predictive value when it comes to the 603e or to PowerPC code.

(Please see the Addendum at the end of this blog post for a real world comparative speed test performed using Photoshop 4.)

Advanced Hardware Issues with the x200 Series

In the Advanced Hardware Issues section Mr. Barber described what he believed to be the motherboard design of the x200 series. The highlights include:

• The 64-bit CPU bus split into two 32-bit buses, “Left32” and “Right32”, with main memory on one half of the bus.
• The CPU forced to act as a bridge between the two buses.
• Components arranged to fill out the bits of a bus and described as conflicting where they overlap.
• A range of mismatched component speeds derived from one clock signal.
• No multiplexers or buffers. Mr. Barber stressed his belief that all multiplexing was handled via software.

Not to put too fine of a point on it, but everything Mr. Barber said in this section was false. Such a motherboard would never work.

To begin with you cannot split a PowerPC data bus in the manner he described. When the processor is on a 64-bit bus it’s going to use all the data pins. If half those lines went to RAM and half simultaneously went somewhere else then an 8-byte or 32-byte transaction would result in a hard crash. In the 32-bit mode there was one single 32-bit bus, not a split bus.

Just as important, the bits of the data bus were not split between devices in order to fill out the bus. All components were connected to the same bits as with any personal computer data bus. They did not interfere with each other because they were address mapped and managed by a strict, hardware enforced arbitration protocol. This is because if two components were to drive the bus at the same time their outputs would be connected leading to electrical damage.

With the article description in mind let’s look at the actual design as documented by Apple.

x200 Motherboard

Far from being bizarre or compromised, the x200 motherboard was very similar to a northbridge/southbridge design:

• The 603 processor, 256K external L2 cache, and ROM shared a 64-bit bus clocked at the same speed as the 603.
  • Addendum: I have conflicting information that this ‘local bus’ actually ran at a max of 40 MHz. This is almost certainly true. This doesn’t change my overall conclusions because the observed performance is what it is. And Apple was still clearly trying to improve performance with a faster 64-bit bus to the L2 cache and ROM. In retrospect I should have dug deeper on this point. The idea that this bus ran at CPU speed, or would have had an L2 cache fast enough to take advantage of those speeds, should have raised a red flag for me.
• A custom chip, Capella, linked the 603 bus to a 32-bit 68040 bus running at 37.5 MHz on boards with the 75 MHz CPU, and 40 MHz on later boards with faster processors. Capella provided 64-bit/32-bit translation and bus arbitration. The ‘040 bus connected the memory controller and graphics controller making Capella similar to a northbridge chip.
• Another custom chip, PrimeTime II, linked the ‘040 bus in a hierarchy to a 16 MHz 32-bit 68030 bus. This bus connected sound, ADB, the floppy disk, and the LC PDS slot which dictated the clock speed and ‘030 protocol. PrimeTime II was similar to a southbridge chip. It had I/O buffers, its own clock, and hardware support for multiplexing both 8-bit and 16-bit devices to the 32-bit bus.

A few other important details to note:

• SCSI, IDE, and serial port I/O was handled via controllers embedded in the F108 ASIC on the ‘040 bus.
• The IDE controller was 16-bit with an I/O buffer.
• There was no on board network controller. The comm slot was just a proprietary expansion slot.

Evaluating the x200 Motherboard

The single thing I see which impacted performance in favor of lower cost was placing the memory controller and RAM on a 32-bit bus. Thanks to the L2 cache this enabled Apple to use more of their existing component designs for a small speed penalty. Given the higher clock speeds and lower pricing of these models it was a fair trade off.

Apple could have reduced the cost of Capella by setting the 603 to its 32-bit external data bus mode. Instead they retained a 64-bit bus close to the processor to speed up the 256K cache and ROM. And they designed Capella so that the 603 could continue to execute instructions from the cache and ROM while the ‘040 bus was busy.

Mr. Barber’s article implies that multiple buses and speeds compromised these Macs. In fact most personal computers from that era to today have multiple buses for the same reason that the x200 did: it allows the motherboard to mix slower and faster chips without compromising the fast ones.

Conflicting I/O & Multitasking in the 90’s

Mr. Barber gave numerous examples of devices conflicting with other devices, such as typing vs. audio and networking vs. graphics, which he blamed on overlapping bits. As explained above the data bus bits were not split between devices, and devices could not simply talk over or block each other at the hardware level.

This does not mean that you would never experience problems like those he listed. In Mac OS classic code was cooperatively scheduled. Busy or errant code could retain control of the CPU and block other processes. Every classic Mac could experience paused and dropped typing; broken audio; screen redraw pauses; and general unresponsiveness while under a heavy load. Windows 9x suffered from the same issues. These types of problems were eliminated with modern OS architectures.

While using a 6300 at home I used various Power Macs at work. I do not recall the 6300 being better or worse than its peers when it came to these issues. And I do not recall Mr. Barber’s specific examples at all. This does not mean that they never occurred for anyone. But they would have been due to software issues and not the motherboard.

Slow Internet Handling

“One of the biggest complaints about the x200 series is slow Internet handling. For one thing, looking at the chart above, all data from either the ports or the ethernet controller must pass through the processor to get to memory, then be processed, sent to the IDE controller for cache saving, and then interpreted for graphics display.”

The developer note indicates that the SCSI and serial port controllers had direct memory access (DMA). It does not specify whether or not other components had DMA. I would guess most components required the CPU to manage I/O. This has nothing to do with multiple buses. A component either has DMA or the CPU must manage the I/O.

But even if the CPU had to relay traffic for an Ethernet card it would not have impacted Internet handling. A 10 Mbps card downloading at full speed would create bus traffic of 1.25 MB/s to the CPU and then to RAM. The ‘030, ‘040, and 603 buses could carry 64 MB/s, 150 MB/s, and 600 MB/s respectively. Relaying the data would require so little of the CPU’s time that the impact would not be human observable.

If the 603 models were noticeably slow on the Internet then it would have been due to the 16K cache and legacy 68K code. As I recall the 6300CD handled the Internet about the same as Power Macs like the 6100 and 8100.

Modem Compromises

“Apple scrimped on the port controller. There is no hardware handshaking in the ports, therefore an external modem faster than 9600 baud is useless.”

An 8530 SCC serial port controller was embedded in the F108 ASIC. The developer note documents the handshake pins and specifically notes that the GPi pin for each port is connected to the controller and available for use. The GPi pin is what’s missing from earlier entry level Macs that limits their transfer speeds.

Adrian Winnard’s tests confirm that later models supported speeds greater than 9,600 baud. I remember removing the internal 28.8K modem from my 6300 and replacing it with an external 56K modem. I consistently connected at near maximum speed. Other users have emailed Low End Mac to say the same thing.

It’s possible that a bug in early hardware or software broke handshaking on the first models. It’s also possible this confusion stems from cabling. Whatever the cause behind some users not achieving maximum serial port speeds, Apple did not leave out the serial port controller or hardware handshaking on any x200 model. And they could not have saved any money by doing so.

VRAM & L2 Cache

“Neither video RAM nor L2 cache are upgradable, but in the case of this machine they would only serve to further slow it down.”

As previously noted the x200 Macs had a fast L2 cache (for the time). Increasing it would have only improved performance. But it sat on a DIMM card with the ROM which precluded any future upgrades.

The video buffer was actually composed of 60ns DRAM chips on a private 32-bit bus connected to the Valkyrie video controller. Valkyrie could not offload drawing from the CPU. But it had multiple I/O buffers so that the CPU could move on to other work instead of waiting for writes to complete. A larger video buffer would not have slowed the computer down except for the obvious implication that there would be more for the CPU to draw.

Road Apples?

In light of the corrections above do these Macs warrant being called road apples and the worst Macs ever?

Not when it comes to models based on the 603e. The desktop models had the same form factor and expansion options that Low End Mac praised in the Quadra 630, which they called one of the 25 Most Important Macs and “…probably the most flexible consumer Mac ever made.”

Eighteen months after the 630 was introduced the 6300 raised the bar with 4x the integer performance, 20x the floating point performance, and a doubling of both hard disk and CD-ROM speeds. Performas based on the 603e were comparable in speed to professional Power Macs released just a year prior. They were excellent Macs for the consumer market.

I never used the models based on the 75 MHz 603 so I have no frame of reference to evaluate their real world performance relative to the few benchmarks still available online. Unlike the 603e the 603 benchmark scores may not accurately reflect their performance because benchmarks did not stress 68K emulation. Still, I can’t help but wonder if a relatively small issue grew into a legend with time. I am now very curious to restore one and see first hand the impact of the smaller cache.

Whatever their performance, the motherboard was not to blame. If Apple’s 75 MHz 603 based Performas deserve their terrible reputation, they deserve it for the lack of a mere 16 KB of on-chip memory.

Addendum: 6300CD vs 6100/66 DOS Using Photoshop 4

After writing the initial blog post I found my old 6300CD and purchased a 6100/66 DOS. I always intended to write a follow up post speed testing the two across a range of PowerPC and 68K applications. I never got around to doing it while I had both machines. I still have the 6300CD. So at some point in the future if I get another NuBus Power Macintosh with a 601 processor I may follow up with that post.

For now I’m adding a set of Photoshop 4 times to this post. These are the only tests which I carefully performed while I had both machines (i.e. checking all settings for speed impact, performing multiple runs, etc). It should be noted that the Performa has been upgraded with a much larger and newer IDE drive which would likely improve operations involving disk I/O. Never the less the tests showed what I expected. The 100 MHz 603e should be roughly 50% faster than the 66 MHz 601. Instead it’s roughly 20-30% faster, and sometimes comes close to 50% faster. Occasionally it falls behind. I’m not sure why the resize test ran faster on the 6100/66, but the result was consistent. The motherboard imposes a small speed penalty, but nothing remotely close to the 4x speed penalty suggested by Mr. Barber. All times are in seconds.

Test Notes:

• Power Mac 6100/66 DOS w/256K L2 cache card, 264 MB RAM, and 350 MB SCSI HDD.
• Performa 6300CD w/256K L2 cache, 64 MB RAM, and a 40 GB IDE HDD.
• Both running System 7.5.5 with Modern Memory Manager on, Virtual Memory off, and 512K of disk cache.
• Photoshop 4 had 40 MB of RAM assigned to it.
• Test file was the 1920×1200 El Capitan Desktop JPEG. All tests were started from the original image.
• No other applications were running and each machine had a minimal set of extensions loaded.

While I had both machines I performed additional informal comparisons. I always found the 6300CD to be a little faster. Blocking tasks would block on either one. Background tasks which were well behaved and did not block on the 6100 also did not block on the 6300CD. I tried my hardest to disrupt audio by typing on the 6300CD (one of Mr. Barber’s specific examples to prove motherboard component interference), but I never could. Network downloads always ran faster on the 6300CD, even with System 7.5 and MacTCP. It should be noted that my 6300CD has a LC PDS Ethernet card, and that this may (or may not) be faster than the comm slot cards available at the time. Regardless, it shows that networking was not bottlenecked by the motherboard design.

Until now that is.

So over the following weeks I will post one article a week about classic Macs until all of them are online.

How did this start? Last summer (2015) I had a bit of nostalgia for old Macs. I’m not sure what triggered it, but I ended up spending a night surfing the web reading about machines from the 1990’s and early 2000’s. I also dusted off a PowerBook G3 PDQ that I had purchased off eBay three years prior but never really played with.

This might have all ended with a few nights of web surfing and playing classic games on the PDQ except for one small thing: a pair of articles at LowEndMac.com. Low End Mac is one of the most popular sites covering Macintosh systems which are…well…no longer current. They have a treasure trove of articles, specs, and tips. They also produce new content on a regular basis.

Those two specific articles stuck in my head because I knew some, if not most of the technical information they contained was false. But I didn’t want to write a rebuttal without being sure. And that led me down a path of old books, tech notes, source code, and memories of writing code for Power Macs running System 7.5 – Mac OS 9. The machines I learned to code on.

I wrote the rebuttal. I also restored a Mac I thought had been lost to time. Found a Mac at a recycling center nearly identical to one I spent hours working on professionally. Hunted for abandoned Macs at local garage sales. And purchased Macs off eBay I that I remember wanting back when they were new.

Some of the machines I’ve restored have already found new homes. Others I will keep. I’m still looking for old Macs to restore and old software to archive for posterity. Maybe something I’ve written along the way will help others restore and enjoy the classics.