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Making Win2k load on an unrecognized processor?

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Old Thrashbarg

Sep 26, 2007
So I have this old dual PII machine that I've been working on. In the process, I swapped out the old Klamath PII 266's for some Katmai 500mhz PIIIs. The machine is limited to 66mhz bus (440LX chipset), so the new chips will only run at 333mhz, and the BIOS mis-recognizes them as dual "Pentium Pro 333mhz," but they work otherwise. I've booted a Linux liveCD and have run a prime test on 'em, and everything checked out stable.

Windows 2000, however, does not seem to be so happy with them. Setup freezes if I try to install with 'em in there, and if I install Windows with the original CPUs and swap them out afterwards, Windows will freeze at the startup screen. I've heard about this problem before, something to do with HAL not liking the mismatch between the CPUID and the BIOS, IIRC. What I want to know, though.... is there anything I can do to get around that? I've tried XP as well, but it does the same thing.

And I already have the latest BIOS on the machine.
ok probably the bios is saying "hey I'm ACPI" and its not. You could see if you can find a bios option for MPS spec and increase this to max, or failing that:

When prompted to press F6 press F5 then choose MPS hal (might be MPS multiprocessor hall)

good luck
ok probably the bios is saying "hey I'm ACPI" and its not.

Well, that's the thing... I was already using the MPS Multiprocessor HAL because of that exact problem. I suppose I could try "Standard PC" just to see if it'll work at all, but that wouldn't give me a real solution regardless, since it'd only recognize one CPU...
Windows will freeze at the startup screen.

Possibly a BIOS setting issue. I know that with XP, it's probably an IRQ conflict or I/O address conflict, especially when the motherboard has onboard sound and you have a SoundBlaster sound card installed without disabling the onboard sound in the BIOS setup.
Possibly a BIOS setting issue.

I doubt it. As soon as I swap the original CPUs back in, everything is peachy. Changing a CPU doesn't usually effect IRQ allocations or any of that.

That's actually what makes this so frustrating... there's no reason why it should be doing this. The CPUs are the only thing being changed (and even then they're not that different... they're essentially PII 333's with a few extra instructions tacked on), and other OSes (Linux, DOS) don't have a problem with it. It's just Win2k/XP.
On some older motherboards there is a reset escd option.
If it is not in bios, have you tried holding delete key and tapping insert key or vise versa to redetect correct cpu while booting?
On some older motherboards there is a reset escd option.

I'll try that, but it seems doubtful it'll redetect the CPUs properly since they are most definitely not supported by the machine. The thing only officially takes up to PII 333's, and while the CPUs I'm using are effectively quite similar, they do use a different CPUID and microcode.

Edit: Hm... looks like I might also do well to try NT4 SP6. I found this link where some guy in Japan upgraded one of these machines with Coppermine CPUs, and NT4 booted without issue. (And luckily I don't have to deal with re-enabling the cache and all that...)

Of course, that would bring up the question: why would NT4 work and 2000 won't?
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perhaps MS had to make some compromises to get all the fancy stuff working under 2k.

or maybe NT4 runs it in apm mode instead of acpi...

speaking of that, does that bios have any acpi/apm related options to try?

speaking of that, does that bios have any acpi/apm related options to try?

It has some limited power management stuff, but it's not ACPI... or, at least, not fully. It seems to be from that era when ACPI was just starting to appear but wasn't actually implemented fully/properly. Either way, though, it shouldn't make a difference since I'm using the MPS Multiprocessor HAL when trying to install Win2k, which [at least theoretically] should bypass all the ACPI stuff anyway.

An update though... NT4 does indeed work fine with the new CPUs. I have it installing now, and it's going through without a hitch. *Sigh.* Guess I'll be using NT4 on that machine then...