annoyed by this few second fps drop from 1 years

[appshot]

oh so here i have a PC

AMD Phenom 2 x4 955 Black Edtion
8 gb ram
crosair gs600 psu
nvidia 650ti 2gb boost edition

I left gaming 1 year ago because of this whatever game i play
MY FPS DROPS EVERY FEW SECOND THE COME BACK TO NORMAL
its very irritation

few days back i wanna start again
thermal pasted the cpu, format the pc , defrag the hdd, freshly installed windows and all the updated drivers
used
MALWAREBYTE full custom scan nothing appears..

No results tried all youtube videos and forum.

Lastly posting here for the fix of any one has thanks.

 

[GhislainG]

You certainly have a motherboard; which one?