need a solution to my low framerates

[new.puree]

I have posted several topics concerning my psu and fan needs but i have tried using a household fan to blow into my base. Still in game, after an hour or so, I start a chaotic cycle of a loss of frames followed by a perfect framerate.
I have a 400 w psu running a 6600 gt and have tried blowing a fan into my case. Is there anything I can do to make this madness stop?? I am running low mid settings and yet this happens every time!!

 

[ilovesocks]

Maybe try reseating your heatsinks? There could be too much or not enough paste (Arctic Silver 5, that is, right? ) on your C and/or GPUs, if you have a custom cooler on your 6600GT.