I run a leser setup with little problems. 5 accounts on one screen with min 15 fps, and max 45. Each core is set to 1 account except for the last 2 accounts on the 4th core. Ram is my only real hurdle, where I get some pauses in Ogrimar as it hits the HD.

Dell xps 420

Q6660 at 2.4
ati 2600 xt
3 gigs of ram
500 gig hd
Vista Ultimate 32 bit