I had this problem about 2 years ago but didnt thought about that it would come back but here i am.. -.-
It's only noticable when you play Computer games that are FPS based.
When you run straight forward its easiest to notice aswell cause you get a little notch/hack/lag at the same time as my computers front lamp is blinking once
and then the lag is over and coming back again after 2-3 seconds and everytime the notch/hack/lag are at the same delay
I got it after i opened a burned CD that has some kind of infection on it ..
But im protected by Sandboxie and Malwarebytes and are scanning at this moment
Men finds nothing .. So please analyse my computer for a error or some cause i dont want to backup and reformat again
Thanks on forehand