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also, re LC-PDS devices: it wouldn't at all surprise me if the graphics and video capture devices are the kinds of things that don't work on the 6200 (or perhaps the 575/580/630) because of the lack of actual "processor direct" access.

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On 4/18/2019 at 12:48 PM, Cory5412 said:

The 6200/6300 all did. I still haven't had a chance to look at the 6300 developer note to see what Apple said there. As far as I know, Apple never published a revision to the 6200 note, so it's possible that the speeds of the 603 bus are different from the two models.

 

Notably, the only things on the 603 bus are the CPU itself, the Calpella, and the ROM/Cache, so none of the existing chips from the 030/040 platforms involved in the 630/6200/6300 platform need to run at "very" high speed. Those buses (the '040 bus connecting Calpella to PrimeTime I/II/III, F108, and Valkryie, and the '030 PDS and i/o stuff coming out of Primetime II run at) run at their own speeds. The developer note for the 6200 does also state the speed of the 603 bus (it says it's the same speed as the CPU frequency) and the i/o bus coming out of PrimeTime II, but it doesn't specify the frequencies of the 040 data/address buses.

 

It's possible that the 040 bus in this machine runs at 37.5MHz, but the 603 bus is disconnected, logically and physically, from the 040 bus and doesn't need to run at the same speed. As the Taylor Design article says, basically  Calpella/F108 is the northbridge and PrimeTime is the southbridge.

You mean this, copied straight from the 5200/6200 Dev Note:

Quote

The internal bus structure consists of three internal buses; the 64-bit wide 603 data bus, the 32-bit wde 68040 bus, and the 32-bit wide I/O bus. The 603 bus is connected directly to the main processor and runs at the same clock rate. An external 256 KB second-level cache and 4 MB of ROM attach directly to the 603 data bus and help to optomize system performance. 

Yes it says the 68040 bus is 32 bits "wde", and that L2 cache is attached to the 603 bus and helps to "optomize" system performance. Typos and omissions aren't exactly foreign to these Dev Notes. Note my previous observation that there are exactly zero references to the system bus speed, only to processor internal clock and the 16MHz of the CS/LC PDS slots. It doesn't mention system RAM speed either.

 

Did you read previously where I noted that there existed ZERO 603 processors that could run at 1:1 processor:board speed exceeding 66MHz? I linked the 603 UM. It's not that many pages. That alone should be enough of a clue that anything physically external to the 75MHz processor on a 6200 is running at a lower rate, specifically no greater than half of that (which is 37.5, if you're curious).

 

Or maybe the fact that absolutely no Apple support chips produced in 1995 ran faster than about 50MHz, including Capella? Even if it did, there's the fact that neither the L2 chips or Capella changed with the increase to 100 or 120MHz 603e models. If the faster 603e chips ran their external L2 caches at 100 or 120MHz, why did they use exactly the same L2 cache modules from the 75MHz models? Were they somehow upward compatible with a >25% increase? And why did the faster 603e require a heatsink while Capella, now supposedly also running at 100 or 120MHz, didn't? It's because everything outside of the processor on the new models ran at 40MHz while the 603e ran at a multiple of that (2.5 or 3x) internally. Again, according to the documents from Motorola, there were exactly zero 603 or 603e chips that could exceed a 66MHz bus.

 

Go boot a 52/62/53/63xx, run TattleTech/Newer Gauge or Clockometer/Speedometer/Metronome/whatever and tell me what speed it has the system bus and L2 caches. I guarantee it's 37.5 on the 75MHz models and 40 on the 100/120MHz models.

 

Anyway going through my cache of Dev Notes, I don't have one for the 6300, only the 5260 which is basically the same as far as the board is concerned: it runs the 100MHz 603e instead of the 75MHz 603. I don't have any Dev Notes for any machines with the 120MHz 603e or the latest variants with soldered ROM and vacant L2 cache slots. These things don't have the greatest documentation.

 

I'll concede the CS/LC PDS thing as being a rare perfect storm, if it happens at all; I've never tried it because I have few non-Ethernet LC PDS cards. However, as you noted with the CS Ethernet and IIe card where "Apple says it won't work", I'll assume this is because the CS and LC PDS slot share the same 030 bus and only one can be active at a time. So basically choose one and forget the other (excepting CS modems, which are basically serial pass-through devices not on the 030 bus). Not that there were a ton of options outside of networking anyway.

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25 minutes ago, Franklinstein said:

I'll assume this is because the CS and LC PDS slot share the same 030 bus and only one can be active at a time

Your guess here is wrong. The stated/accepted reason is because CS devices want/use 32-bit addressing mode.

 

In reality, it might actually work, who knows. There's been some work, if I remember correctly, on running the IIe card in the 580/630, and that same work might allow it to work in a 575 with an ethernet Comm Slot device. (if it's been successful, I dont' know the status on that.)

 

However, CS ethernet should work with other PDS devices. that was never a documented as a limitation of any of these systems.

 

29 minutes ago, Franklinstein said:

Or maybe the fact

Okay, conceded. We've gotten a little beyond the point of my statement which is that the Taylor Design article, while having a technical error or two (based on Apple's own writing) is the most correct available after-the-fact assessment of those machines.

 

I have a 6220/75 at home, as I've said, it's "fine" with PPC native code -- I've run 7.6.1 and 9.1 with a couple different apps, which TBH almost everything I happen to use is, I'll pull out some older 68k versions of things and poke around with it at that point.

 

The other thing to remember here is that, again, a 6200 with a monitor, keyboard, mouse, a raftload of software, and usually a modem or a printer cost 1/5 of what a 9500 with a mouse and a text editor cost. It cost around half of what a thusly equipped 7500 cost, and if you added a keyboard and monitor to a 7200, you were also at about two 6200s.

 

It was an insanely good deal, for which there was a compromise if you bought, borrowed, or already had certain kinds of older software.

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Wow, this sure turned a little heated. My one comment:

 

On 4/19/2019 at 5:54 PM, Cory5412 said:

I have a 6220/75 at home, as I've said, it's "fine" with PPC native code

If PPC being able to run mostly native code gives these machines a new lease on life, that's totally great, but... in context, if these things really were dogs with 68k code because of the emulation simply being flatly inappropriate for the CPU that genuinely would have been a big deal when they were introduced, and you can't blame people for bearing a scar from it. Remember, these things were introduced running System 7.5.1, and with that version of MacOS almost the entire OS runs in emulation on PPC. It probably did genuinely suck.

But, yes, it's been completely run into the ground that the LEM article that was passed around for years about these machines is positively, completely, and utterly bunk, to the point of "not even wrong" in a lot of places. These boxes basically are just what the technote pretty much comes out and says, IE, they're low-end Quadras with CPU upgrades, and when Apple shoved them out the door Quadras with CPU upgrades were still considered viable platforms. They should mostly be judged by that standard.

(Although I guess you could be catty and point out that at least most Quadra upgrades let you switch back to the 68040 if the emulation speed got you down...)

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The OS itself being bad until a couple years later would definitely be a bummer. A thing I should absolutely do, and probably will, is pop an original 5200/6200 install CD in my system and run some applications on it to see what that's like, relative to how 7.6.1 and 9.1 perform on it. I might do that in the mid-near future, because my network card isn't running so the OT/AS updates needed to hop on VTools aren't exactly relevant at the moment.

 

One thing that I'm interested in is if we've got an exhaustive list of what was in the bundles on all the variants of these things when they shipped, and whether those things were native/fat or 68k. From a "being scarred" perspective, I feel like (and, granted, I mean, I'm 31 today so if my family had one of these things at launch I would have been 7 and the understanding of computing a 7-year-old can have vs. a 30-something can have is very different) "something the machine came with" is unusable is pretty different than "something we borrowed or bought" is unusable.

 

That doesn't excuse it and to my knowledge Apple added no disclaimers or other notes about the potential for 68k-native software to have poor performance, but even if something is "clear" it doesn't mean it will be understood, see Microsoft Surface RT being marketed as "A PC!" for a more recent example.

 

As to why I bring it up so often: 1) it continues to get asked. 2) I want it to be abundantly clear to anybody reading this from afar who might have one of these machines or be able to find one, but, not, say, a Quadra 950 or a Power Mac 9500 that these machines are worthwhile both in 1995 and today.

 

From a 1995 perspective, yeah, if you were upgrading from something and the new machine you bought ran your particular apps (in this case, it appears to be that "games" is the only class of application impacted in any noteworthy way) much worse than your old one, you'd be unhappy. The 6200 wasn't really marketed to upgrading Mac buyers, but that wouldn't have stopped them from getting one.

 

From a 2019 perspective, it's not at all difficult to put a newer OS, speed-doubler, and maximize the use of PPC native apps and do whatever puttering you wanted to on this machine, about as well as any other vintage Mac would've done it. A corner of an edge of us are actually using these vintage Macs for something a 6200 would have a real hard time doing, and fewer of us than that group are *actually* doing those things, rather than just kind of touring them.

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I hate to add fuel to this fire, but I noticed last night that the 603 section in Wikipedia's PowerPC 601 article references the beyond-wrong LEM article as pretty much the sole reason why the 603 was so unpopular (in fact, according to the Wikipedia article, the 603 was the first to fully implement the PowerPC architecture). In reality, the 603 is actually pretty good, and the only reason it wasn't so great in the 6200 was the tiny cache, which the subsequent 603e and 603ev fixed, along with a die shrink so the whole works could be clocked higher. This has been discussed ad nauseum here, of course, so I won't blather about it anymore; I guess i just wanted to point out that the LEM article apparently has been around long enough that it has become quite pervasive, and thus there are many references to it (some of which aren't where we'd typically expect them) which assume it is fact when it isn't.

 

c

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What's worse is if someone tries to go fix it, some rando wiki editor who knows literal zero things about Macs is going to revert it and point directly at LEM as the authoritative source about the 6200 as a platform, even though we have Apple's own documentation about the platform.

 

In reality, I hadn't thought of going to make those changes myself, but, I mean, I could certainly give it a go.

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8 minutes ago, Cory5412 said:

What's worse is if someone tries to go fix it, some rando wiki editor who knows literal zero things about Macs is going to revert it and point directly at LEM as the authoritative source about the 6200 as a platform, even though we have Apple's own documentation about the platform.

Why not write the correct article in the Wiki here at 68kmla, then cite it in that Wikipedia article in place of the faulty article?

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That's absolutely a good beginning point. I figured it would be easier to cite the actual develoepr notes, which we do have, they exist, etc etc.

 

The other thing to remember, I'm sure everybody knows this, is that it's not just one article on LEM, it's like five articles on LEM and almost every subsequent fluff piece on bad apple products includes this misinformation.

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22 minutes ago, Cory5412 said:

The other thing to remember, I'm sure everybody knows this, is that it's not just one article on LEM, it's like five articles on LEM and almost every subsequent fluff piece on bad apple products includes this misinformation.

Yeah, but ya gotta start somewhere. :D

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8 hours ago, Dog Cow said:

Yeah, but ya gotta start somewhere. :D

Truer words have never been spoken!!

 

c

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11 hours ago, Cory5412 said:

 I figured it would be easier to cite the actual develoepr notes, which we do have, they exist, etc etc.

Oh you mean cite the Apple dev notes in the Wikipedia article? I think that's even better.

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On 4/16/2019 at 10:17 PM, Franklinstein said:

Nothing outside of supercomputers ran external cache at CPU speed, ever, at least not once CPU speed started to decouple from bus speeds in 1990-something. No way Apple was going to pay for 100MHz SRAMs for a bargain basement computer.

The access timing of RAM is a distinct issue from the speed of the bus that it's on. You'll find many examples...especially among early Macs...of the same speed RAM (cache or main memory) being used across computers with different bus speeds. It's possible that the developer note is incorrect and that the 603 bus ran at 37.5 MHz (2:1). But L2 cache access timing doesn't prove this so.

 

Case in point: many Macs at the time used 80ns RAM SIMMs which were interchangeable across machines, including these Performas. If RAM access timing strictly dictated bus speed then they would all have had 12.5 MHz system buses.

 

Quote

According to Motorola's user manual for the 603, this is a non-standard and unsupported configuration: the 603 is designed to only run at 1, 2, 3, or 4x bus speed, with a variety of supported bus speeds. However, 37.5 is not one of them; the 75MHz part is designed to be run at 3x a 25MHz bus. while the fastest 1:1 speed available for the 603 is 66MHz.

Running a 75 MHz part (or an 80 MHz part @ 75 MHz) at 2:1 for a bus speed of 37.5 MHz is a non issue. Just because Motorola didn't list it as an example does not mean it couldn't be done or was outside their design specs. I can think of plenty of examples of part manufacturers listing common configurations and system manufacturers tweaking the speeds up/down a little bit.

 

Having said that: I find it curious that the 603e manual also lists the highest external bus speed as 66 MHz. I could dismiss the 603 manual as being written before newer parts, including newer versions of the 603, were available. But the 603e manual suggests 66 MHz was a 'hard limit' at the time for these processors. If that's true then naturally the external 603 bus could not run at 1:1 with a CPU running at 75, 100, or 120 MHz.

 

I'm going to do a little more research, but my gut feeling is that you are correct on this point and that both the 603 and 68040 buses ran at a multiple of the core CPU speed. I'll add notes to the blog posts if that's the case. Good catch!

 

Also: if anyone can document any other technical errors in either of my articles, please let me know. I will gladly correct them.

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On 4/19/2019 at 5:54 PM, Cory5412 said:

I have a 6220/75 at home, as I've said, it's "fine" with PPC native code -- I've run 7.6.1 and 9.1 with a couple different apps, which TBH almost everything I happen to use is, I'll pull out some older 68k versions of things and poke around with it at that point.

I nearly grabbed a 6200 on Craigslist one time because I very much wanted to test it against the 6300 and the 6100/66 on PPC and 68K code. Lost the chance and haven't seen one locally again.

 

TBH I'm very curious about how the 6200 did perform in general (since most of Mac OS at the time was still 68K) and with 68K applications.

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Most of what I've put on mine is PPC stuff. By the time you get to bigger software or newer software, it's not exactly a spring chicken, either. It's absolutely most at home with 7.6.1 or 8.1 and with PowerPC native apps from the 1995-1998 era, and even then, lighter-weight ones. I meant to do some MacBench testing, but MacBench (4, at least) tests PPC if you're on a PPC Mac and I haven't found a way to force that. 7.6.1 or 8.1 PPC-ifies just enough of the OS to make a couple things better, relative to 7.5, but is still relatively lightweight. Speed Doubler 8 may also help.

 

My Mac Pro is in the spot the 6200 was in, now, but I'll swap things around again and see about how I can record usage of the machine. For worse or worse, this will involve either buying capture hardware, or pointing a camera at a monitor and hoping for the best.

 

It's probably worth noting, by and large with a similar load-out, the Power Macintosh 6100 isn't exactly a speed demon either. I don't know if that's a "dying hard disk" issue or if it's just, the early, low-speed PowerPC Macs are all slow. I suspect most people "forgive" the 6100 by either never using it, or upgrading it with a G3.

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2 minutes ago, Cory5412 said:

Most of what I've put on mine is PPC stuff. By the time you get to bigger software or newer software, it's not exactly a spring chicken, either. It's absolutely most at home with 7.6.1 or 8.1 and with PowerPC native apps from the 1995-1998 era, and even then, lighter-weight ones. I meant to do some MacBench testing, but MacBench (4, at least) tests PPC if you're on a PPC Mac and I haven't found a way to force that. 7.6.1 or 8.1 PPC-ifies just enough of the OS to make a couple things better, relative to 7.5, but is still relatively lightweight. Speed Doubler 8 may also help.

I definitely judge these machines on how they performed at the time for their price. It's not really fair to judge them based on how they compared with newer machines at a time when Moore's Law was in full swing. I agree with you that they run best with 7.6.1. or 8.1.

 

Quote

It's probably worth noting, by and large with a similar load-out, the Power Macintosh 6100 isn't exactly a speed demon either. I don't know if that's a "dying hard disk" issue or if it's just, the early, low-speed PowerPC Macs are all slow. I suspect most people "forgive" the 6100 by either never using it, or upgrading it with a G3.

I wouldn't say the early Power Macs were all slow. But with the exception of later 604e machines, they were all slow compared to a much newer G3. I remember that G3 based Macs, including the iMac, felt incredibly fast at the time. I don't think OS X felt as "snappy" as OS9 on a G3 until the G5's arrived.

 

My 6300 consistently out performs my 6100/66 (with cache card and plenty of RAM) even when using 7.5 or 7.6 and early Mac networking software. Not by leaps and bounds. By a small but consistent amount.

 

Quote

My Mac Pro is in the spot the 6200 was in, now, but I'll swap things around again and see about how I can record usage of the machine. For worse or worse, this will involve either buying capture hardware, or pointing a camera at a monitor and hoping for the best.

Or just report what you find.

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12 minutes ago, Cory5412 said:

Also! Welcome! I cite your articles very frequently!

Thank you! I actually joined a while back but only occasionally lurked. This thread caught my attention and wasn't so old that it felt weird to reply.

 

I wish I had time to play with classic Macs and make more blog posts. Some fond memories of that era.

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Side-note about G3s: I have a Beige G3@300 and an 8600/300 and the G3 outperforms the 8600 at least 3x in integer and either matches or is 2x in floating point, I'll have to look.

 

It's utterly wild how much faster the G3 was than everything else.

 

Anyway, if you compare, like, 6200-based architectures (most of the PowerBooks up until the 2400/3400 then the G3) to the PCI machines, the PCI machines pull ahead massively.

 

But, again: in the US in 1995, $1900 got you a 6200 with software, games, an encyclopedia, a modem, a printer, a monitor, and a mouse. That's very clsoe to at or below entry level on every other PowerPC desktop until a couple years later.

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On 4/17/2019 at 5:26 AM, Franklinstein said:

 In addition, no Apple support chips in existence at that time could operate beyond 50MHz, let alone up to 66MHz. If they did, don't you think the 9500 would operate at the same speed? Why would their flagship have slower parts than their cheapest machine?

Apple support chips may not have been spec'd to run faster than 50 MHz, however, they will operated well over 50 MHz.  I've run the PM9500 and the related Umax S900 at a 62MHz bus speed, using a PowerLogix PowerBoost Pro PPC604e based card.   The special thing about the PowerBoost Pro is that it adjusts the Clock ID pins as the bus speed is changed.  The Clock ID pins are CPU slot pins that tell the logic board chips what bus speed range to adjust to.    Most of the G3 upgrade cards didn't even use the Clock ID pins, which is why so many of htem would not operate at a bus speed above 45 MHz.  They were all letting the motherboard logic default to a  40 MHz setting.

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18 hours ago, Cory5412 said:

Side-note about G3s: I have a Beige G3@300 and an 8600/300 and the G3 outperforms the 8600 at least 3x in integer and either matches or is 2x in floating point, I'll have to look.

 

It's utterly wild how much faster the G3 was than everything else.

 

Part of that performance increase is probably caused by the switch from 60 or 70 ns FPM memory (14 - 17 MHz) to 66/83 MHz SDRAM.   The RAM access in the G3 based machines was at least 4 times faster.   Oh, and the faster backside L2 cache vs. slower In-line L2 helped a lot to.

 

Similar to the 6200, I've always been dismissive of the Mac IIvx because the of the 1/2 speed bus.   But thinking about it more, the RAM can't deliver data any faster than 16MHz any way and I don't think any of the peripherals run that fast.  So does it really matter that the CPU runs at 32MHz and the bus only runs at 16 MHz?    Perhaps, for all these years, the IIvx was actually a good machine....

 

According to LowEndMac the IIvx tests 30% slower than a IIci.   That doesn't seem to make sense in theory.  There must be more to it.   Perhaps the cache running at only 16MHz makes that much difference?

Edited by trag

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6 hours ago, trag said:

Similar to the 6200, I've always been dismissive of the Mac IIvx because the of the 1/2 speed bus.   But thinking about it more, the RAM can't deliver data any faster than 16MHz any way and I don't think any of the peripherals run that fast.  So does it really matter that the CPU runs at 32MHz and the bus only runs at 16 MHz?    Perhaps, for all these years, the IIvx was actually a good machine....

 

According to LowEndMac the IIvx tests 30% slower than a IIci.   That doesn't seem to make sense in theory.  There must be more to it.   Perhaps the cache running at only 16MHz makes that much difference?

The IIci and IIvx used Fast Page Mode (FPM) RAM. This means the initial time to access a random location was 80ns, but the subsequent 3 reads from the same row were much faster. Fast enough to reveal the difference in the bus speed.

 

There's also all the other traffic on the board to consider, and how that might have impacted performance given the 16 MHz vs 25 MHz difference. As you point out for a lot of peripherals it wouldn't make a difference, but I wonder what impact video had.

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Generally, my Take about low end or otherwise "compromised" systems is that they got that way somehow, and the somehow is usually because the computer-buying public wanted a less expensive computer.

 

In the case of the 6200, a 6200 bundle (with a keyboard, mouse, software, monitor, encyclopedia, and usually a printer or modem) cost around a third of what a basic 9500 cost, before you added literally anything to the 9500. (Granted, that proportion goes down a lot if you compare the 6200, more realistically, to a 7200 or 7500.) A fully equipped 6200 cost just about the same as a bare 6100, and the two run PowerPC-native software at roughly the same speed.

 

The IIvx mostly gets compared to the Mac IIci. I don't have exact pricing and performance information, but I imagine that it pans out pretty similarly to the Performa 600, which I detailed below, and in a thread I linked.

 

I think the thing that a lot of people forget is that the Macintosh isn't just DTP and Photoshop and video production, but it's an entire platform representing a ton of different use cases. That the Performa 600  or 6200 isn't good at some of them shouldn't doom the machines to be forgotten or intentionally destroyed, it's just.... these were basic computers meant to be affordable introductions to the current hot topics in computing when they were new.

 

The Performa 600 in particular, based on the IIvx/vi, heavily emphasized the potential for convenient, inexpensive CD-ROM multimedia. The 6200 features that in full swing, and to my recollection, most 6200 configurations include a modem for access to the Internet or other online service.

 

 

8 hours ago, trag said:

Part of that performance increase is probably caused by the switch from 60 or 70 ns FPM memory (14 - 17 MHz) to 66/83 MHz SDRAM. 

I think platform improvements end up being very important in computer performance issues. It's easy to ignore the fact that everything about the Generation 3 PowerPC Mac platform is radically faster than the previous machines.

 

I also love the G3 macs because Apple dumped the prices on them several times, shifting the price of the basic desktop G3 all the way down to $1299 before the series was discontinued in favor of the blue-and-white models. That's a bit shy of a thousand dollars short of where that class of machine was two or three years earlier.

8 hours ago, trag said:

Similar to the 6200, I've always been dismissive of the Mac IIvx because the of the 1/2 speed bus

 

The IIvx (and IIvi and Performa 600) came up in a thread a few weeks ago. I reviewed the original MacWorld review of the P600 from 1992, when they compared it against the "similar looking on paper" Mac IIci, which, while older, has a much higher end overall design.

 

That discussion was here:  (the link should hopefully go directly to my post on March 9.)

 

Paraphrased: Slow isn't necessarily bad. Context is everything.

 

The Performa 600 (I haven't yet looked at a IIvx review) benches at about half the speed of the years-old and still much more expensive Mac IIci. Ultimately, the way to reconcile that is to remember that the Performa 600 (and ultimately the IIvx and IIvi) were never intended to be sold as a replacement to the IIci -- that was the Quadra 700. Instead, they were meant to be inexpensive and "good enough" for budget-constrained use cases. They were, helpfully, upgradeable in a couple ways. (NuBus slots, video RAM, CPU upgrade slot, the cache slot is said to be disabled or not present in the P600, at least by MacWorld in 1992.)

 

The Performa 600 was a lot less expensive than a IIci and was a "good enough" system if you wanted to have a computer but didn't need or want to pay for Quadra performance.

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16 hours ago, dtaylor said:

The IIci and IIvx used Fast Page Mode (FPM) RAM. This means the initial time to access a random location was 80ns, but the subsequent 3 reads from the same row were much faster. Fast enough to reveal the difference in the bus speed.

 

That makes sense.   It would depend on the CPU actually reading four locations per transaction.  Was that "burst mode"?  Did the Mac actually make use of it?

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14 hours ago, Cory5412 said:

 the cache slot is said to be disabled or not present in the P600, at least by MacWorld in 1992.)

 

The Performa 600 was a lot less expensive than a IIci and was a "good enough" system if you wanted to have a computer but didn't need or want to pay for Quadra performance.

 

The IIvx had a 32KB cache soldered down on the motherboard.  The P600 (assuming these two boards I just got are P600 boards) have empty pads on the motherboard where the cache chips could go.   So it's probably possible to add the cache to a P600, just not easily done and not by most users.  There's also an FPU socket present (PLCC package, not PGA).

 

The article you referenced in the other thread had some interesting performance comparision tables.   It would be interesting to me if they had also included the IIci performance with its cache removed.  

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