I recently decided to upgrade my old gateway gt5670 pc. I installed a coolermaster extreme 500w psu and an Evga 9800gt. It works fine I havent seen any problems atm when I play cod4, the gameplay is smooth and gpu usage is average at 90% but when I play a mmo game which requires lower reqs, I get a low gps and only a gpu usage average an 5%. The fps I get ingame is between 10 to 25. It drops to 5 when I walk to crowded areas.
Sorry if made any typos, typing this on an itouch.
More about9800gt usage game
I thought that the MMO games are CPU bound.
Well my friend's gpu usage was average at 50% when he's playing with me and his gpu is a 9500gt.
I believe he has a dual core amd cpu and mine is a triple core.