@Harbourboy
Not much, but higher than mine (just watched)
I got a quad-duo 2.4 on Abit IP35, 2 Gb RAM, nVidia 8500 GC, running WinXP Pro.
Have you look for an updated BIOS?
Drivers are surely important, but BIOS too.
Be care when you update it.
BTW i never experienced a crash during a game, only on loading from a game (knockin' wood).