My understanding is that you need 8 MB RAM to do 1024x768 in 3D with the Mach64.

My notebook only did 800x600 in Windoze, so you might be lucky and have a better chip than I do.

I don't understand your reference X11 versus XFree. When I said I run two X11 servers I meant two XFree86 X11 servers.

Dell has a number of models with NVidia cards. Here's my list:
- Dell Latitude D800 (not D600)
- Dell Inspiron 8600
- Dell Inspiron 5150
- Dell Precision workstation M60
- The current Compaq/HP AMD-64 notebooks (Gefore 4 4x0Go, older
generation and DirectX8 but not really slower than the FX 5xx0
stuff)
- Alienware Area-51
- www.powernotebooks.com has a few models but only with 1024x768
displays.

To the best of my knowledge, there are only two full-featured, stable, and open-source X11 servers out there at the moment. (I don't remember if they're both still X11R6 or not.)

XFree86 is the oldest one.
X.org has a different license and was forked off from XFree86 originally.
(I didn't know about X.org's origins until I read the Beyond Linux From Scratch eBook)