I'm not sure exactly why, but the guys at winhistory.de managed to install Windows XP on a 20 megahertz Pentium 1 system with 32 megabytes of RAM:
theres no such thing as a 20mhz pentium chip. this is clearly photoshoped.
before the pentium was the 486 33mhz so i doubt a later model chip would run slower than the earlier model. i think there was a pentium 75mhz and im sure there was a p90, because thats what most people had at the time.
definately no p20 because its impossible.
maybe it’s a Pentium 120? perhaps windows has problems recognizing double digit speeds. Like that roadside radar dealie I passed last week at 120… it just read 20… 
I think the slowest Pentium was a 60mhz.
I once installed Windows 95 on a 486DX2/66 as a lark. You could literally see the window chrome being drawn, the background being filled, etc. It was pretty funny.
Perhaps XP’s catalogue of processor names doesn’t go as far back as 386SX? Hence, in this demonstration, XP was not actually running on a Pentium machine, but a 386SX/20?
If you guys read the link, what they did is use the motherboard jumpers to severely underclock the board. The other trick they did was to install it on a system that met the minimum requirements (64MB RAM), and then take that install and move it to a crappier machine.
At an old job, I had to install Win 95 on the minimum for some compat testing. 386 CPU with 4MB RAM. Sure, technically you can “run” the OS in that setup, but it starts swapping if you just right-click something. It took literally 5 seconds to get a context menu.
If there is a hell, that’s what the computer there are like.
Yeah, it only had 2 megs of memory. Pretty low. Lots of disk swapping.
I like the picture of the Osborne Executive. It reminds me of a “portable” IBM computer that I used to have to lug back and forth when I was the yearbook editior in highschool. This was an 8086 processor with a 7" amber display. The keyboard folded up into the case which was at least 24" x 18" x 10". The thing must have weighed at least 30 pounds since the monitor was built in. It was probably one of IBM’s first portables. Yikes!
I ran Win95 on a 486-66 with no problems. The trick is to make sure that you had enough memory. Win 95 really needs at least 16 MB of RAM which was a lot back then.
I ran Win95 on a 486-DX2-66 with 4MB of RAM. I later upgraded to 8MB and it was quite snappy.
Dang, I could have sworn I posted a response to this.
The multipliers on old Pentiums (up to the P2-333) are unlocked. That means you can set the system speed to any valid multiple of the bus speed. The minimum Pentium bus speed is 60mhz.
The board they used has some oddball bus speed jumpers that let them get down to 25 mhz and 20mhz. Those are 486-era bus speeds!
It’s all in the article, although their translation to English is a little… rough.
I once installed Windows 95 on a 486DX2/66 as a lark
Win95 should be fine on that system with enough memory… lots of 486es around in 1995 still!
theres no such thing as a 20mhz pentium chip. this is clearly photoshoped.
before the pentium was the 486 33mhz so i doubt a later model chip would run
slower than the earlier model. i think there was a pentium 75mhz and im sure
there was a p90, because thats what most people had at the time.
definately no p20 because its impossible.
You could at least try to pretend that you’d read TFA, he’s running a Pentium I/60 underclocked at 20MHz.
Yeah, it only had 2 megs of memory. Pretty low. Lots of disk swapping.
Well, that’s weird, because 4mb was the minimum memory spec for Win95. They had to cut a LOT of corners to fit it into 4mb.
I have installed windows xp sp1 on a pentium 1 133Mhz and 80mb ram. It runs a little bit slow but does the job. I also installed ms office 2003 and it still runs. I have 2 HDD a 4GB and a 30GB. Too cool.
I am using a 486 Laptop with 4MB of RAM and 25 Mhz of Processor. It has Windows 95 installed on it. It runs quite slow but i browsed the internet with it (A 56K Modem that worked on COM Port). I couldun’t install a decent browser like IE 5 but Mosaic worked. I could also view my e-mail with Microsoft Mail. I make my job with it.
Well, it is funny i came across this crazy page because the minimum for windows xp is 233 proccesor with 64 megs ram. i am as we speak installing it on a 200 that i overclocked to 210 and it is actually working fine, not real fast but stable. i will go in and shut down all the crap services and the unessecary display features though
I time a go i ran Win95 on a 386-sx 25mhz with 8MB of RAM and a 4g hard drive with a 8 bit isa graphic card. I later upgraded to 16MB, it delayed 9 hours to install windows 95 and 3 hours to install the IE4, it was running the 16 colors, when the windows as on it run prety good with the basic windows aplications
Ok Thats Not Really A Reall Windows Xp
Its Called TinyXP Its A Windows That Makes Your Computer Look And Work Like Windows Xp And Plus You Can Install It On Any Old Computer I Got A Pentium 1 150MHz With 1.2GB Hard Drive And 128MB Of Memory And Its Working Really Fast So Search For TinyXp To Download It Its Really Small Windows Xp And I Would Only Install It On Any Old Computers Like A Computer That Is Under 400MHz Becasue TinyXp does not have any drivers it only got really old drivers for old computer So search TinyXP And Download It
Your Computer Needs To Be
Between 20MHz To 400MHz
32MB Of Memory
600MB Hard Drive
CD Rom
Thats All You Need To Run TinyXp And To Make It Fast
SEARCH TinyXP Now To Download It
Go To http://torrentpond.com And Search TinyXP
Great unbeliaveable, but truly the minimum speed for x is 100 or 133 mhz.
I tried at 133mhz CPU CELERON SOCKET 1. with 64mb ram the simm type 1mb vga. hdd 1gb. with su 90 watts.