Just need some advice

Ok so maybe I'm a bit of a perfectionist when it comes to things and with games like metro I'm getting 30-40 frames on ultra , with Battlefield 3 I get lag spikes a lot ( I heard other reports though) and In wow in the new expansion zones I'm getting 30 frames( heard other people have this problem also) and whenever I tried to install texture packs for morrowwind i only get like 30-40 frames or qarls for oblivion it lags like crazy and Shogun I get huge lag with shogun on some occasions especially siege battles. Is something bottlenecking it? Its not heat issues ( I checked) or do i just have to learn to turn my game settings to medium or am I just lucky to get 40 frames on games like metro?

Specs
i5 650 3.4ghz dual core
6 gigs of ram
gtx 560 ti 1 gb v ram
windows 7