XP Minimal-Requirement-Test

The target of this project was to find the weakest system where you can run Windows XP. Keep in mind, that Microsoft official requirements are a CPU with 233 MHz an 64 MB of RAM. But that had to be beaten! Read now about the contest of Antz and me, and how it will all end in hist record in january 2006.

First try: Socket 5, Pentium 100 MHz and 64 MB RAM

Experimental setup 1

  • Gateway 2000 socket 5 mainboard
  • Pentium 75 MHz overclocked to 100 MHz
  • 64 MB RAM, later > 32 MB
  • SCSI Harddisk and CD-ROM
  • Winner 1000 graphicscard (ISA)

The setup worked without any problems, you only had to spend more time. Windows found a Pentium, but it does not matter if it is a Pentium I, II, III or IV. The 64 MB of RAM are at the setup MINIMUM, if you have less at this point you get a error and the setup will be ended before it really started. The installation or starting of XP on a 486-system is NOT possible. We tried it (see below).

After the setup XP is not as fastidiously as before, you can easily remove memory. With 16 MB XP will not start anymore, you have to have a little more, see Test Two.

Back to the CPU, after removing the RAM, it will be set to the original clock: 75 MHz, which is the lowest cpu clock on this Board and the lowest cpu clock for most socket 5/7 Boards. For the 16-colours you had to install an ISA-graphiscard. XP does not really support this cards anymore....

First result: Socket 5, Pentium 75 MHz and 24 MB RAM

Second try: Socket 3, Pentium Overdrive 83 MHz and 64 MB RAM

Experimental setup 2

  • Arstoria AS496 Socket 3, SiS 496/97 Chipset
  • Pentium Overdrive @83Mhz and 63MHz
  • 64Mb RAM, final 18MB
  • IDE harddisc 6.4GBaund CD-Rom
  • S3 Trio32 PCI Grafics

At a new try to install XP on a 486-system, Antz has succeeded to install it on a socket 3 mainboard (the last socket for 486 cpus). However he used a Pentium Overdrive. This very fantastic kind of technics has an original Pentium core, but with a 32-bit memory-controller specially constructed for the 486 socket.

Although he wasn't able to use a 486 CPU with this board and XP, he had to set up new records for mimum CPU and RAM

The cpu clock is a composition of  the 33 MHz systembus and a buildin multiplicator of 2.5 (33 MHz x 2.5 = 83 MHz). Antz had clocked the systembus down to 25 MHz, and with this lower systembus the got 63 MHz (25 MHz x 2.5 = 63 MHz).That is the new cpu record!  (XP rounds down on 62 MHz)

The memory record was reached with the usage of the 32-bit memory-controller, an ordinary pentium has a 64-bit memory controller and does need 2 Edo modules (they have a 32-bit interface), but this one only needs one modul of Edo.

So he tried 24 MB RAM (2x8 MB + 2x4 MB), then 20 MB RAM (2x8 MB + 2x2 MB) and at last: 18 MB (2x8 MB + 1x2 MB). And it works great, but the systeminfo shows a wrong size of RAM: 20 MB ... but in the taskmanager you can read the real memory size.

Second result: Socket 3, Pentium Overdrive 63 MHz and 18 MB RAM


Antz has successful reduced the cpu clock. He only removed the fan of the Overdrive cpu. The fan is power-supported by the cpu, so the cpu can check this and if the fan is missing ,a pentium overdrive will set the multi to one. So the cpu runs of 1x25 MHz instead with 2,5x25 MHz. The time for booting is about minutes.

New second result: Socket 3, Pentium Overdrive 25 MHz and 18 MB RAM

Third try: Socket 4, Pentium 60 MHz and 64 MB RAM

Experimental setup 3

  • Elitegroup SI5PI AIO (REV. 1.1) Socket 4
  • (Installation: Socket 5 Board from Test 1)
  • Pentium 60 MHz
  • 64 MB RAM, later 32 MB
  • SCSI harddisc and IDE CD-ROM
  • Voodoo Rush PCI graphics

To beat the CPU-record made by Antz I used the first Pentium-processor: the Pentium 60 MHz. It runs synchronously with the frontsidebus, so it have a multiplicator x1.

But to the beginning a bad surprise: XP always crashed every time in the first part of the setup. Because I had no idea why, and nothing helped I did the same as in my  "Windows 98 on a 386-system"-try: I changed the board for the time of installation. So I used the board from test 1, and the whole process took about 4 hours.

When I changed the boards XP needed a very, very long time to start up, because it installed the new mainboard devices, but finally: it worked! Until today I don't know what the setup made crash.

It is really simple why I had not chosen another Board (I have a second with Intel chipset), this one can be set easily with the jumpers "S0", "S1" and "S2". Too many jumpers for the two marked modes 60 and 66 MHz. So I tried to jumper in otherways, one of this tries was:

S0 (J7) S1 (J6) S2 (J5)
2-3 1-2 1-2

25 MHz!

At the jumperblock, the jumpers 5,6,7 regulate the systemclock=CPU clock. Here they are set to 25 MHz.

I have found 50 an 33 MHz too, but why so much power? Of course I halved the memory down to 32 MB. I could not remove more, because I did not own the right modules and I had to use pairs of Edo (64-bit memory-controller...).

When you only run the desktop without any special program, the cpu does not have not much to do, if you do this at a 25 MHz computer and Windows XP you got a lot of waiting.

One short look in the systemmanager. The list is rather short, the Rush does not have any driver and there is no CPU (but the mainboard chipset is correctly identified).

But I had not finished, and I tried on:

S0 (J7) S1 (J6) S2 (J5)
1-2 1-2 1-2

20 MHz!!!

Although this clock is not possible on most socket 3 Boards, this one makes it! For what reason this is jumperable? I do not know...There were rumors about a Pentium 50, but the official lowest Pentium is the one with 60 MHz. Perhaps it had something to do with the turbo-switch, they were working not uniformly.

The "only-windows"-boot (from the end of the initialation of the BIOS to the first icons on the Desktop) will take about seven minutes, but you have to add a few more minutes until you can start to work. And remember this system is very "naked": No sound, no high-res graphics, no USB...

The CPU is working at full capacity to 60 % when you are only  using the Desktop! Nowadays with a modern CPU you had to run much tasks in background to reach such a high level of work.

For this reason you have to be patience very often. Did you ever notice the changing of the blue color on the screen before the "Welcome"-page?? You can see all 8 blues line by line with 20 MHz??? Every single window will build up in elements for seconds:

By the way, Windows XP runs with 20 MHz more worser than with 25 MHz. At 20 MHz everything was loading much longer, and not every cold-start was successful... But it's a new record!

Third result: Socket 4, Pentium 20 MHz and 32 MB RAM

Fourth try: New socket 3 Board and again Pentium Overdrive

Experimental setup

  • Asus PIV-486SP3 Socket 3 Mainboard, SIS 496/97 Chipset
  • Pentium Overdrive 83 MHz @ 16/8 MHz
  • 64 MB RAM, later 20 MB
  • EIDE drives
  • Vision964-PCI graphics

Antz strikes back. With an equal setup like in try number two and a Pentium Overdrive (without fan) downclocked to 16 MHz, which you can set with the jumpers JP25-28 on pins 2-3.

The installation was made with the help of nLite during the night.

With a little try Antz have made it. The frontsidebus was set down to 8 MHz, XP runs now with the clock of an ISA Slot!

The clock is so little, that the PCI graphics card was unable to boot correctly, so Antz had to install an old ISA graphics-card. On the first turn he used a Acance Logic, secondly a Cirrus, because this one allows a 256 colors. The ethernet-card is more stable, it is PCI but runs still with 8 MHz, so you can access the internet without a problem. Of course you need time, the homepage is availible after 10 minutes.

If you have the same board, here are the settings for jumpering of 8 MHz:

2-3 2-3
1-2 1-2

The boottime of this system is extremly long, 30 minutes! After 13 minutes you can see the first icons, but there are 17 minutes more, where you can do nothing, before you can start "working".

Of course the cpu is alltime at 100% all the time, there is no real idle mode:

Now that's quite difficult to strike this, perhaps with a laptop, when you can there can set the clock stepless ...

But until this the record of the lamest XP PC goes from Berlin (Germany) to Vienna (Austria).

The golden Sandclock Award
For extreme waste of time.

Fourth result: socket 3, Pentium Overdrive 8 MHz & 20 MB RAM

Benchmarks zu den Versuchen:

  Pentium 20 MHz
(Win XP)
Pentium 25 MHz
(Win XP)
486 SL 25 MHz
(Win 95)
Pentium Overdrive 16 MHz (Win XP) Pentium Overdrive 8 MHz (Win XP)
Norton SI 4.0, DOS 63,4 79,2 53,8 50,7 25,3
SiSoft Sandra 2001 Dreystone (Windows) 43 MIPS 54 MIPS not possible
(Win 95)
SiSoft Sandra 2001 Whetstone (Windows) 22 MFLOPS 21 MFLOPS not possible
(Win 95)
DrHardware 5.5
Hardstones (DOS)
16743 20998 11088 14921 7317
DrHardware 5.5
Softstones (DOS)
7287 9142 4902 5830 2915
393,60 sec 305,13 sec. 311,40 sec.    
time to boot 11 Min 9 Min 2 Min 14 Min 30 Min
cpu use in idle 63 % 46 %   52 % 100 %

Benchmark Screenshots


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