WORLD RECORD: XP on a 2 MHz pentim(pcem-x)

[ovctvct]

Nobody tried it, so, lets see:(I will try a 486 mobo too soon) It was heavily nlited, installed with 233 mhz and 192 mb ram. ( I will post further results later)
first try: PI 75 mhz and 96 MB ram:


EDIT: Changing mobo gives NTLDR missing error. :/

Check out last post!

[Windows OS]

Hmm. This should be fun! As far as I know, Win2k will still run on CPUs as old as the i486 SX at 25 MHz. Let's see what will happen when you choose older...

[computebrute]

Hmm. This should be fun! As far as I know, Win2k will still run on CPUs as old as the i486 SX at 25 MHz. Let's see what will happen when you choose older...

If you try, you can run it on a 386. The world record is Windows XP on a 16Mhz (Underclocked) Pentium with 32MB RAM.

[Windows OS]

If you try, you can run it on a 386. The world record is Windows XP on a 16Mhz (Underclocked) Pentium with 32MB RAM.

And that's because XP requires the CMPXCHG8B instruction, which the Pentium introduced. However, I'm pretty sure that a hardcore geek could patch the kernel not to detect or use that instruction, like what happened with Windows 8: http://www.betaarchive.com/forum/viewto ... 62&t=28824

[MSUser2013]

If you try, you can run it on a 386. The world record is Windows XP on a 16Mhz (Underclocked) Pentium with 32MB RAM.

And that's because XP requires the CMPXCHG8B instruction, which the Pentium introduced. However, I'm pretty sure that a hardcore geek could patch the kernel not to detect or use that instruction, like what happened with Windows 8: http://www.betaarchive.com/forum/viewto ... 62&t=28824

Actually the record for XP is a 4MHz Pentium Overdrive with 18MB of RAM, See here for proof.

Windows 2000 (Along with Whistler builds 2223 and earlier) will run on a 486, You can try changing the CPU on your Pentium system to an IDT Winchip which is a 486 equivalent Socket 7 CPU since it's detected as an unsupported CPU on XP setup. It will not run on a 386 since Windows NT 4.0 won't work on a 386 either so 2000 will definitely not work. You can try NT4 betas on a 386 though.

Offtopic Comment

I was experimenting with patching XP to remove the CMPXCHG8B instruction and I think the only place where it checks the CPU for that is when you insert the setup CD, So I've tried replacing Setupldr.bin (Which does check for it) on the boot disk with the one from Build 2223, It no longer checks the CPU, But it BSODs when it gets past "Setup is starting Windows 2000".

[Windows OS]

Offtopic Comment

I was experimenting with patching XP to remove the CMPXCHG8B instruction and I think the only place where it checks the CPU for that is when you insert the setup CD, So I've tried replacing Setupldr.bin (Which does check for it) on the boot disk with the one from Build 2223, It no longer checks the CPU, But it BSODs when it gets past "Setup is starting Windows 2000".

Hmm. That gives me an idea...

[ovctvct]

About the IDT, yes, it seems to work, however the lowest available is 75 mhz,I want to know if it can be underclocked... seems it can't be, and to try a 486 mobo reinstall is required but once done cpu can be set as low as 16 mhz 486, and possibly even lower by underclock in BIOS. XP record was 8 MHz pentium overdrive, 2k record was 4 mhz downclocked 486. I'll try the 486 mobo asap.

75 MHz IDT winchip running 2000(seems slower than the Pentium one for some reason):


GPU is a S3 Trio 64 with 4 MB of vram. If I will manage to get it work below 16 mhz, I will need to use an ISA vga.

Boot time is only ~1 min(because I added /NOGUIBOOT in boot.ini), also, CPU usage for the P1 was 19%, notice how IDT is at 26%, way slower.

EDIT:NO, PCem-X clearly has a bug with 486 mobos and hdds, no reinstall is required, but for some reason I keep getting INACCESSIBLE_BOOT_DEVICE BSOD every startup on those mobos Until that gets fixed, it is impossible to run on a 486 UPDATE: I FINALLY got setup on 486 to work! Now hope it will finish.

EDIT:NOPE:


However, 98 SE worked in that config, here's 98 on a 16 MHz 486 SX and 24 megs ram, and only 512 KB vram, hence why it is only 256 color(everest doesn't even want recognize the 486 cpu for a reason):

[win98]

Great project idea, I might join in having a play when my uni stuff is done for the year as I'm interested to try too.

75 MHz IDT winchip running 2000(seems slower than the Pentium one for some reason):

Win Chips were pretty budget things if your interested they have a bit of info on what made them slower and what was actually better vs a Pentium at the link below. (TLDR they were simpler but had more cache) - I'm abit of a geek when it comes to the history of x86 CPU's as its interesting to see what was made to compete with Intel etc.
http://www.cpu-collection.de/?l0=co&l1=IDT&l2=WinChip

[ovctvct]

UPDATE: Thanks to Battler for telling me why win2k in 486 didn't work: HDDs larger than 1.9 GB seem to fail on a 486, mine was 3.0 GB so, anyway, I am reinstalling it on a smaller HDD right now and I will post any eventual results here. The 98 HDD was 1.5 GB so thats why 98 worked and win2k didn't, oddly I didn't notice this until now. This time I am installing win2k on a IDT winchip 240 MHz (fastest CPU PCem-x can emulate) with 256 MB ram this time, and then switch to the 486, because otherwise setup on a 486 would take 5-6 hours.

EDIT: IDT is NOT fully compatible with 2k it seems, during the 2nd part of setup, I got some odd error message and I had to switch to an intel mmx 233 MHz to get it work. But at least IDT works after setup...
EDIT 2: Setup finished. Now I am switching to the 486. FAIL, it still wont boot on the 486... then i must reinstall... i choosen 1.85 GB, that shall work. OK, reinstalling on the 486, but with an amd 5x86 p75+ at 150 mhz, hope it works.. No, I wont give up too easily.
EDIT: Almost done installing on the 486 mentioned. Temporary specs: AMD am5x86 p75+ 150 MHz CPU, 1.85 GB HDD(to comply with the 1.9 GB "limit"), s3 trio 64 4mb, 128 MB ram, Award SiS 496/497 motherboard. Nearly 4 hours passed since I begun install and it STILL has not actually finished lol

I'll leave this shot of setup to prove it is possible until it will finish:


Uh, I cant believe it!


First 486 result:

63 MHz overdrive and 64 MB RAM:


Second result: i486 DX 33 MHz &32 MB RAM, 16 bit color(65536 colors, because vram=1MB)(takes a long time to boot lol:~10 minutes):

"Unknown" CPU, again.

And... 16 MHz i486, finally! But with 24 MB RAM, its nearly unusable. Not to mention long boot time.


Here's the CPU clock displayed while it boots, to prove i'm not lying:

[ovctvct]

Sorry for double post, but despite this topic seems ignored I did not give up and I have decided to install XP on an overdrive 83 MHz in pcem-x and it's almost finished, results will be posted soon.(nlited again of course)

It has 128 MB ram(the mobo I use supports up to 256) for the moment, to make install faster. After I will (hopefully) underclock it the ram will be reduced.



63 MHz:


(XP rounds it to 62 Mhz)

Update:I have taken the latest pcem-x source code and finally managed to modify the cpu clock to low values(within the source code, of course). I will post results later. (the latest pcem-x doesn't support the motherboard I used with the xp install, so I will need to reinstall it)

RECORD: XP on a 4 MHz- current world record is 8 mhz overdrive - (underclocked, obviously) pentium - takes about 1 hour just to boot...


everest shot to prove it:


Forget about Antz at winhistory.de, this is the new record!

One more picture:(taken with a cell phone, not print screen, sorry for the quality but I'm not really good with taking pics)

[Procta]

how quick do these boot then?

[ovctvct]

how quick do these boot then?

I have not measured boot time for all of those, but:

XP on 4 MHz- one entire hour (from POST to desktop)
XP on 63 mhz overdrive ~3 minutes
XP on 83 mhz overdrive ~2 minutes
2000 on 16 Mhz 486 SX: ~10-12 min

[oscareczek]

Just wow O.o But I think Pentium 4 MHz is faster than Pentium Overdrive 4 MHz, so maybe…? And I'd use vanilla XP, SPs increase system requirements.

[ovctvct]

Just wow O.o But I think Pentium 4 MHz is faster than Pentium Overdrive 4 MHz, so maybe…? And I'd use vanilla XP, SPs increase system requirements.

That's because of the L1 cache mostly, and the 64 bit data bus(overdrive has 32 bit) which can be disabled easily in the BIOS. But an overdrive has 32 KB cache while this has only 8 so... The 8 MHz overdrive, according to winhistory.de took 30 mins to boot while mine took about 1 hour so it's still slower. Plus, I could even try 2 MHz pentium which is even slower. Vram is 512 KB so that can't make it faster. I don't really think a SP would increase required specs since it is so heavily nlited that it only takes about 500 megs of hdd space.

[cantasan99]

Does XP check the processor speed as a minimum requirement to boot and run?

[oscareczek]

If so, it wouldn't boot on that silly frequency.

[DallasCHVN]

I'd love to see XP on 1mhz

[ovctvct]

Update: Managed to do a new record: with 2 MHz pentium! But since everest takes a lot to load, I will post screenshots later. EDIT: Boot time is ~2.5 hours and everest STILL has not finished loading lol... Even the mouse pointer is horribly laggy at this clock! This system can crash very easily.

Shot(I know it still didn't load lol)


edit: everest takes too long to start, i will leave the shot above instead.

[Battler]

- ovctvct: PCem-X supports both the 430VX and the SiS 496/497. You just need different BIOS'es now, as the old ones required an UMC UM8669F Super I/O chip of which no datasheets exist (so it was mostly guesswork), while the new one requires a SMC FDC37C932FR, of which datasheets are readily available, and it is much better too.

[DJ Deedahx]

Update: Managed to do a new record: with 2 MHz pentium!

Whoa. 2 MHz? Even IBM 5150 PCs had a faster clocked CPU...

You might as well head to the Guinness World Records website and submit that, will you please?

[yourepicfailure]

You might as well head to the Guinness World Records website and submit that, will you please?

Juding by how Guinness judges, you will need an 100% genuine microsoft CD of Xp, along with it running on *verifiable* bare metal.
Have fun underclocking a p5.

http://www.ebay.com/itm/Merit-E-O-A-Win ... SwZVhWRR~v
Here's a good machine to try, though I may buy it. Only problem I see is the PCI, so you may need to find some ISA cards.

My 8086 is faster than your project thing lol.

[ExplicitNuM5]

Juding by how Guinness judges, you will need an 100% genuine microsoft CD of Xp, along with it running on *verifiable* bare metal.
Have fun underclocking a p5.

Offtopic Comment

Not to mention you need some verified Guinness judges standing next to you and your computer, taking notes, watching the computer and you, just standing there... Waiting for >1 day for it to boot up.

[miker00lz]

EDIT:NO, PCem-X clearly has a bug with 486 mobos and hdds, no reinstall is required, but for some reason I keep getting INACCESSIBLE_BOOT_DEVICE BSOD every startup on those mobos Until that gets fixed, it is impossible to run on a 486 UPDATE: I FINALLY got setup on 486 to work! Now hope it will finish.

First of all, awesome speeds! lol. I was wondering if you could help me out though. I'm getting the INACCESSIBLE_BOOT_DEVICE error, even if I use a drive smaller than 2 GB. I've tried 1 GB, same issue. What exactly did you do you get around this? Would be grateful if you let me know what the deal is here.