I have a i7 920 with 12 gigs of memory. I can run 5 instances in Dalaran with no problem. I just replaced my q6600 quad core /8 gigs ram which could NOT even come close to running 5 instances in Dalaran (100% cpu load). Only difference in the systems is the i7 920 w new MB vs q6600 and 12 gigs vs 8 gigs. The upgrade was about $600. $220 for i7 920, $180 for 12 gigs memory, $220 for MB.