Yes, it will. 😀

The people at winhistory.de did some experiments with XP on old hardware.

https://www.winhistory.de/more/386/xpmini.htm

English Translation

Jo22 wrote on 2020-08-06, 20:53:

Yes, it will. :) […]
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Yes, it will. 😀

The people at winhistory.de did some experiments with XP on old hardware.

https://www.winhistory.de/more/386/xpmini.htm

English Translation

But that's not really a 486. It's a Pentium bolted to a 486 socket.

XP's kernel has Pentium instructions, so even though it will boot on a POD underclocked to 8MHz, it won't run on a true 486. Not even a 100MHz DX4.

Standard Def Steve wrote:

won't run on a true 486. Not even a 100MHz DX4.

Hi, I think it depends on point of view.
On the other hand, a lot of people don't consider a 386 mainboard with a 486DLX/SLC CPU or Rapidcad CPU as a true 486, either.
On the other hand (again), some people don't consider an am586 or 486dx4 as real 486 CPUs, either.
The latter seems strange, but the 486dx4 was said to have incompatibility issues with some 486-optimized games.
Perhaps because it was not based on the original 486 design anymore, which the 486DX2 also was based on.

Sorry, I probably wasn't clear on my intent.

If I installed WinXP on a Pentium Overdrive Socket 3 system, then replaced that Pentium overdrive with a 486 DX4-100, would XP run?

Looks like ntoskrnl.exe has some cmpxchg8b instructions in it. Unless it's carefully coded to avoid doing those on a 486, it would crash as soon as it hit one.

Yeah XP would never run on a 486 even if you swap CPUs after. It's not a requirement "on paper" like most things, it really needs those instructions. I've seen some 486 XP bullshitters before...

Win2000 will run on a 486 though! Probably not after a certain service pack however...

Kind of the same issue people are facing with all sorts of stuff requiring SSE2 now vs. their Pentium III and Athlon XP machines.

leileilol wrote on 2020-08-07, 00:18:

Win2000 will run on a 486 though! Probably not after a certain service pack however...

Win2000 is kinda special also, because it was the last OS to run on PC-98 platform.
It also was the last OS with useable HPFS support and an intact POSIX and OS/2 subsystem.
W2K could even run Presentation Manager programs for OS/2 1.x once that mysterious "Microsoft OS2 Presentation Manager For NT" was installed.
In this respect it was really a professional OS, IMHO. If it had its GUI running in user-mode, like NT 3.x had, it would have been perfect.

It's also possible the kernel will check the processor on every boot rather than just at install time. It isn't like Win95/98 where processors without cpuid were supported.

Thanks for the replies! Guess Windows 2000 is the latest and greatest for this machine.

I do have Win2000 SP4 running on it already. Nice little OS and surprisingly usable even on a 486.

Was going to say latest but not so sure on greatest?
But as you seem happy enough with its speed I guess it's true.

is this the IBM in your sig? Ran NT4 on a DX2/66 with 64MB Ram towards end of it's life back in the day. Took an age to start but once booted it mad for a good basic office/internet PC for homework, etc and lot more stable then 95
it also left the faster PC free for gaming 😀

jakethompson1 wrote on 2020-08-07, 00:26:

Kind of the same issue people are facing with all sorts of stuff requiring SSE2 now vs. their Pentium III and Athlon XP machines.

Even the socket 939 Athlon 64s are hitting a wall at Windows 8.1. They don't support the "CMPXCHG16b" instruction and either crash/reboot when starting the install (my experience) or report "You can't install Windows 8.1 because your processor doesn't support CompareExchange128." (according to The Internet)

chublord wrote on 2020-08-07, 01:49:

Thanks for the replies! Guess Windows 2000 is the latest and greatest for this machine.

I do have Win2000 SP4 running on it already. Nice little OS and surprisingly usable even on a 486.

That's cool. I will have to try that. If everything works I would be able to get my USB wifi adapter (that surprisingly enough had Win2k drivers and utilities) working on a 486, that would be very useful.

Did you have to do anything special to get it running?

The real question is why would you want XP running on a 486? NT4 and 2k were already taxing enough as it was. Even on my PIII-700 Windows XP felt like a dog compared to 2k.

I'd say its the challenge to get the newest possible copy of windows running. Not to actually use it.
like how some like the challenge of upgrading windows 1 or whatever to 10, Can't image anything worse to actually use but can understand the appeal of the challenge alone then simply format the thing

Anonymous Coward wrote on 2020-08-07, 12:31:

The real question is why would you want XP running on a 486? NT4 and 2k were already taxing enough as it was. Even on my PIII-700 Windows XP felt like a dog compared to 2k.

Must depend on the amount of RAM and version of XP, then.
I remember that Windows XP was the "best" OS for my Pentium MMX 166MHz with 64MB RAM and a 2GB SCSI HDD.
It was XP that made it possible that SNES9x ran playable first time. It could run TinyToons more or less smoothly (with frameskip).
Other emulators that used to crash on 98SE
previously, ran fine on XP at first time.
Personally, XP was a relief for me. Even on totally underpowered hardware.

I'm not sure what it was about XP that made SNES9x run faster, but pretty much everything I ran on it was slower (and less stable). Better directx support?

Anonymous Coward wrote on 2020-08-07, 12:31:

The real question is why would you want XP running on a 486? NT4 and 2k were already taxing enough as it was. Even on my PIII-700 Windows XP felt like a dog compared to 2k.

I'm still trying to get this connected to my distributed computing client (BOINC). It's not going to add any meaningful computing power to it, but would be cool if it worked. The client is not compatible with Win2000.

chinny22 wrote on 2020-08-07, 10:57:

Was going to say latest but not so sure on greatest? But as you seem happy enough with its speed I guess it's true. […]
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Was going to say latest but not so sure on greatest?
But as you seem happy enough with its speed I guess it's true.

is this the IBM in your sig? Ran NT4 on a DX2/66 with 64MB Ram towards end of it's life back in the day. Took an age to start but once booted it mad for a good basic office/internet PC for homework, etc and lot more stable then 95
it also left the faster PC free for gaming 😀

Yeah that's the machine in my sig. More RAM would definitely help for Win2000 but it's ok to use. Increasing the FSB speed from 33 to 50 MHz made a huge difference in "feel".