WoW seems to be more CPU heavy than some games (HL2 runs almost fine at almost max settings at 1024x768). It's the middle of summer, and roasting here, so I put it back down to 2.0. When I have it at 2.3 (Highest it will go with 1T, dual channel, and value ram =\) the game seems to gain about ~10-15 fps.
As long as the performance is the same, I'd rather get it for $70, sell the 3000+ for $25, and have a nice cheap $45 upgrade. And with it I could watch movies / listen to music with no fps loss. I could grab it and another GB of ram to make this system last until next fall when I build again.
EDIT: It has been forever since I kept up with hardware and such, but doesn't gaming at a low res make you more cpu limited?