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What Mac OS Version is best for PPC Macs that are bad at 68k emulation?

Cory5412

Daring Pioneer of the Future
Staff member
+1 Speed Doubler 8 is a nice boost even on the PCI PowerMacs. It may well make an even earlier system than the 533MHz G4 match the Quadra 700 at floating point. :p
 
The 6200 had a PPC 603 processor which had very little Level 1 cache and this made it struggle with 68k emulation allegedly because it couldn't hold the emulator in cache. The PB 5300 has more L1 cache in its PPC 603e chip and no Level 2 cache (I can't remember - did the top model have an L2???).
The 68k emulator for PowerPC was rushed because Apple had earlier planned to use Motorola's RISC processor. I believe initially the 601 was going to be able to run 68k code through a hardware emulator. Apple's 68k emulator was rewritten for the PCI Mac ROMs. It was rewritten again for the Classic Environment, which can run some 68k apps that wouldn't run natively in Mac OS 8/9.

Given the limited resources on a 5300, I'd normally run it on 7.6.1 with SpeedDoubler to be honest.
SpeedDoubler replaced Apple's slow 68k emulator with Connectix better version.
 

Arbee

Well-known member
The original 68K emulator was slow because it was an interpreter. while (1) { uint16_t opcode = read_memory(PC); switch (opcode) { case 0x4e71: break; } } more or less. So fixed overhead is baked into every instruction. Both SpeedDoubler and the PCI emulator were DRC/JIT, where it actually translates the instructions once into executable PPC code (and can optionally run an optimization pass, like any compiler). So the first time a piece of code runs it's technically slower than an interpreter, but after that it's effectively native.
 

Snial

Well-known member
The 68k emulator for PowerPC was rushed because Apple had earlier planned to use Motorola's RISC processor. I believe initially the 601 was going to be able to run 68k code through a hardware emulator. Apple's 68k emulator was rewritten for the PCI Mac ROMs. It was rewritten again for the Classic Environment, which can run some 68k apps that wouldn't run natively in Mac OS 8/9.


SpeedDoubler replaced Apple's slow 68k emulator with Connectix better version.
@Phipli , @3lectr1cPPC , so does SpeedDoubler (or at least the 68K JIT extension) make any difference to MacBench 4.0 performance on the 5300 / 1400 / 6100 series under Mac OS 7.6.1 (68K finder?) or Mac OS 8.1 (native Finder)?
 

Phipli

Well-known member
@Phipli , @3lectr1cPPC , so does SpeedDoubler (or at least the 68K JIT extension) make any difference to MacBench 4.0 performance on the 5300 / 1400 / 6100 series under Mac OS 7.6.1 (68K finder?) or Mac OS 8.1 (native Finder)?
I don't tend to use MacBench, but if it uses any 68k code it will.

I tend to use SpeedDoubler on my 5300 and 1400. It makes a good difference, especially with older OSes.

Remember that the best solution is to run PPC software though, the speed improvement is way more than anything an improved emulator can give.
 

LaPorta

Well-known member
Probably just me…but usually they all work just fine. I’ve never been dissatisfied running 7.1, 7.5.5, 8.1, 8.6, 9.1, 9.2.2…depending on the hardware. My IIfx uses 7.1.1, my PT Pro has partitions to use 7.6.1, 8.6, or 9.1. In its case, it has a G3 card in it, and all three OSes seem just fine. I usually use 8.6 on my G3 upgraded 1400 w/ 64 MB RAM…and it works great. Can’t get 9.1 to run on it for some reason…

Anyhow, my experience is they all run great unless you are running stuff on 1st gen PPCs or something. For instance, on a 6100, 8.anything at least feels slower than, say, 7.6.1…numbers nonwithstanding. Just my completely non-scientific observations.
 

Phipli

Well-known member
Probably just me…but usually they all work just fine. I’ve never been dissatisfied running 7.1, 7.5.5, 8.1, 8.6, 9.1, 9.2.2…depending on the hardware. My IIfx uses 7.1.1, my PT Pro has partitions to use 7.6.1, 8.6, or 9.1. In its case, it has a G3 card in it, and all three OSes seem just fine. I usually use 8.6 on my G3 upgraded 1400 w/ 64 MB RAM…and it works great. Can’t get 9.1 to run on it for some reason…

Anyhow, my experience is they all run great unless you are running stuff on 1st gen PPCs or something. For instance, on a 6100, 8.anything at least feels slower than, say, 7.6.1…numbers nonwithstanding. Just my completely non-scientific observations.
The PB5300 and PB1400s we're talking about are the same speed as the first generation Nubus PPC macs. Some PB5300s are similar speeds to 6100s
 

Snial

Well-known member
I don't tend to use MacBench, but if it uses any 68k code it will.
I always imagined MacBench tested both PPC and 68K code to take into account emulation performance, but I could be very wrong there.

I tend to use SpeedDoubler on my 5300 and 1400. It makes a good difference, especially with older OSes.
Which reminds me, is there a definitive list of which OS components were native for each PPC Mac OS? Perhaps there's a simple AppleScript that could search through all the files looking for PPC code?
Remember that the best solution is to run PPC software though, the speed improvement is way more than anything an improved emulator can give.
Yes indeed! And in turn that depends on the task you're doing. So, e.g. I understand that the Finder in Mac OS 8 went native, so Speed doubler would help a lot with System 7.x's Finder. But Mac OS 8.x is much heavier than System 7.x, so it feels slower anyway.
 

Phipli

Well-known member
I always imagined MacBench tested both PPC and 68K code to take into account emulation performance, but I could be very wrong there.
I'd argue that doing so gives an underestimate of performance retrospectively with appropriately selected PPC software.
Yes indeed! And in turn that depends on the task you're doing. So, e.g. I understand that the Finder in Mac OS 8 went native, so Speed doubler would help a lot with System 7.x's Finder. But Mac OS 8.x is much heavier than System 7.x, so it feels slower anyway.
Really, if you have the RAM, 8.5 is the big improvement. Takes longer to boot, but runs code faster. My 66MHz PPC in-a-IIci even benchmarks better under 8.5 than earlier OSes.
 
Yes indeed! And in turn that depends on the task you're doing. So, e.g. I understand that the Finder in Mac OS 8 went native, so Speed doubler would help a lot with System 7.x's Finder. But Mac OS 8.x is much heavier than System 7.x, so it feels slower anyway.

I don't find that to actually be true. Mac OS 8 was still using the same old System 7 kernel until 8.6. It's all the extra stuff added on top as extensions and control panels that use the resources. A lot of those are moot now, like Software Update, external media drivers, Multiple Users, etc. They're just RAM munchers, even though I now have ungodly amounts of RAM in my classic Macs.

And then there's the fact that the older versions of Mac OS didn't multitask and didn't cooperatively task very "cooperatively". So doing one thing at a time is much less intense.

I immediately preen everything out of any classic install, add a few things, and then it runs about like 7.5 for me. Nothing is as fast as 7.1, but when you start adding extensions to get 7.1 compatible with later software, you're kind of at 7.6/8.1 territory anyway. Also, the HFS+ support in 8.1 makes everything SO much easier ever since macOS stopped supporting HFS.
 

Snial

Well-known member
I don't find that to actually be true. Mac OS 8 was still using the same old System 7 kernel until 8.6.

And then there's the fact that the older versions of Mac OS didn't multitask and didn't cooperatively task very "cooperatively". So doing one thing at a time is much less intense.

I immediately preen everything out of any classic install, add a few things, and then it runs about like 7.5 for me.
Fair enough, so what's your Mac OS 8.6 extension and control panel setup then? And what's the resource requirements?
 
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