Stuttering in most games please help

I've searched all over google and this site and haven't been able to find any solutions that worked.

I've been having stuttering every few seconds in some games while i have good frame rates and no other lag. In other games sometimes they will freeze completely for about 30 seconds to a minute every 15 minutes or so, or even just crash completely(the main problem is the microstuttering though). I have tried defragging, running anti virus, underclocking gpu, overclocking gpu, setting cpu to run at maximum all the time, and a bunch of other things. The games i experience this most in are BF3, dungeon siege 3, deux ex human revolution, and far cry 2. I get this problem no matter the graphics settings in most cases, it does happen on older games too.

My Pc:
Windows 7 64 bit
4 gigs of ddr3 ram
Amd phenom ii X4 925 (2.8ghz)
Ati radeon HD 5770
1 tb hard drive