I've run RedHat 7 and Mandrake 8 on a 200Mhz Pentium with a <2GB hard 
drive.  On the older machines, you just need to make sure you've got 
RAM.  I had 128MB and KDE ran just fine.

Jonathan Hutchins wrote:

>----- Original Message -----
>From: "Jeremy Fowler" <jfowler@westrope.com>
>
>>>What's the lowest level of hardware YOU have actually USED XWindows on?
>>>
>
>>Well, me personally? PII 350 w/ 64MB ram...
>>
>
>I've had it run satisfactorily on a PII 400, weven with KDE.  I seem to
>recall that I tried it on a P 166 and didn't have much fun, and that was
>pre-Gnome/KDE.
>
>I had some Compaq P120's and P200's with imbedded graphics adapters that I
>tried several installers on about a year ago and they all barfed when they
>tried to go graphical, which I thought did not bode well for XWindows.
>
>
>
>