6990 weird lag spikes

You can see my rig in the sig I got an 6990 and it makes some weird spikes lag and what is weird is that its not even in games so I'm not sure if its really the gpu or its another part but what I know is that the card when its running make a normal sound and lets say when I'm the menu of a game and I'm going thru the menu I got some little lag that seems to come from the gpu since I can ear the sound stop and go at the same time as the lag. I can be wrong maybe its just because the video card doesnt receave the information or wtv... Im using 2x4g rams from a 12g kit (triple channel) in a dual channel mobo Ive been told thats its probably not the problem but I give you all the information I have I also OC the cpu to 4.7ghz ive also try to remove the OC and it doesnt matter the lag spike is still there. But what is weird is that in game there's no lag ... Lets say I'm in starcraft 2 menu if you are familiar with the game menu you know the space in background is lagging with the lag spikes.

Between Ive order another 6990 I wanted to do a 6990 quad system but I will do some trouble shooting with the new card to see if its normal.

Is it only happening in Starcraft 2?

Sorry I was out for a week. No it happens in many games... metro2033...crysis 2

I have had problems like these before, I formatted the comp and it sorted it. I have also had similar problems again and i went through the comp removing parts, i took all ram out and then tried them one by one and turned out all the sticks were fine, but the number 3 ram slot on the mobo was some how defective, any ram i put into it caused problems, so then i just avoided that slot untill i upgraded mobo.
Im guessing that its going to be either hard drive related or a problem within the OS itself though. Hope you clear it up soon mate

haha you freak me out I hope its not the mobo O_O XD