Well.
from what I've gathered and not being that knowledgeable about video cards (I don't play pc games for a start, will when I get a good enough computer though, lol). Have you made sure you have gotten rid of all of your temp/unnecessary files? It also might pay to run an optimisation program like TuneUp Utilities or System Mechanic, do a windows update, check your driver versions, etc.
Might also pay to check in the processes tab of task manager, Spy Sweeper can sometimes eat up a lot of CPU... Depending on what's on your system and the version of Spy Sweeper that you're using. Also, Norton is a hog, use something else.
Also, this might help:
http://forums.pureoverclock.com/archive/index.php?t-16.html