Welllll...
with PP it all depends.
I'm using an Intel Mini ITX board (I guess it is D201) with on board graphics and PP + PCI PP as second one for pendant. OS is Win XP :)
Untill today, no hickups with Mach3, and I've been running quite hefty codes of more than 500,000 lines.
Only thing that I have switched off is toolpath display as Max RAM that the board can accept is 2 Gb, and is shared with graphics chip (if my memory servs me it is a SiS one).