when i play skyrim on my system on high setting it lags when im in a city but my gpu% never goes past 50% (gtx 550 ti oc @1ghz) i have my game caped at 40fps so every where else in the game its always 39-40 fps
At only 720p I'm surprised the 3.0GHZ Athlon II X3 is struggling. And most games make little to no use of the 'missing' L3 cache. In fact, now I'm even surprised the GTX 550ti is struggling at that rez. How and why are you capping the frame rate? And why at 40 fps?
Have you cleaned your system of crap that wastes Windows resources, and registry errors that cause slowdowns lately? If not, try CCleaner: http://www.piriform.com/CCLEANER Do the Clean and Registry both.
When you installed your GTX 550ti, did you remove the old driver first?
im capping my frame rate with evga precision and i cap it because i rather have constant 40 fps vs 40-60 because when it drops i can see some lag....but now i have no lag beacuse i overclocked my cpu to 3.6 and updated my game to version 1.5 and now i can play maxed out with 34-40 fps with no problem (every thing on ultra and aa maxed out )