What kind of games are you playing? I have the same video card as you and some games lagg/frame rates kinda bad. For the game F.E.A.R. that video card is kinda not great, i still see frames moving around here and there. I also just got the game UberSoldier and that game kinda laggs. But i have 512mb of ram so that kinda explains it, but for the framerates its the video card. Turning game settings to "medium" or "low" should do the trick but not much.