I ran Vista RC2 x64 for a while with an X2 4400+, 4GB RAM, a 150GB Raptor, and a Geforce 6600 128MB. It sucked. Say what you want about Vista not requiring much graphics power, but today's low end (or in my case, last year's lower mid-range) GPUs just won't cut it for 1600x1200 single monitor usage (and I'd hate to see how a dual monitor setup would perform!).