GPU Usage goes from 99 to 0%

Gpu usage goes form 99% to 0% when i'm playing games like arma 2. When i'm in a dayz server i sometimes 15 - 20 fps on some servers but in singleplayer ARMA 2 i get over 60 fps. Is there something wrong with my Gpaphics Card or is it normal for gpu usage to do this?

Arma 2 and DayZ have terrible gpu optimization, it'll probably be fixed in DayZ standalone.

Run Furmark stress test for a few hours and see if your windows crashes just to be safe.

Also, what gpu do you have?

A Radeon HD 7950

This also happens in Bad Company 2

Have you installed the latest drivers?

What brand & product number of 7950, specifics.  Bad Company 2 could be a driver problem, but I'm pretty sure Arma 2 and DayZ is a game coding problem.  Still I'd run stress tests just to make sure it isn't on a hardware level.  Furmark, Prime95, memtest... you know.

yes i have the latest drivers

I have it overclocked to 1100 core and 1450 memory and when i run furmark the gpu usage switches between 100 and 64% every few seconds but mostly it stays on 64 %. This even happens with no overclock. I had a problem earlier with this card showing a black screen with only a cursor for the windows 8 login screen but that has somehow sorted its self out. Also temps are good 30 degrees idle and never goes above 60 playing arma 2.

My HIS 7870 used to throttle down to 64% in furmark. I returned it and got a Gigabyte 7870 after my HIS started crashing.  AMD cards will throttle down to 64 in furmark with there is a power problem.  The capacitors were bad on my HIS, so that's why it was throttling.  Do you have your power up to +20% in CCC?

Also, link me your power supply. I doubt it would be that, but just to be sure...

I checked again and my gpu wasn't throttling in BC2 , also i haven't change any settings in CCC yet.

Well open it, go to performance, and change the power slider to +20%

Corsair is a good brand, extremely minimal chance that it's the power supply.

Changing the power slider to +20% should fix it. 

Think of it as a classic car.  Gas = PSU, Engine = GPU, that slider = Carburetor.  If it's set too low then your engine isn't getting enough gas when it really needs it and starts to sputter out.

I can vouch for Brents answer. The same thing happpened to me when I was trying to test and bench my card. Set the power to +20% and everything will be fine.