Lag spikes in BF3

Hello!
I am experiencing strange performance issues in bf3 multiplayer.

The game is set to ultra with lower AAs. The fps normaly is between high 70s and 60s (In some areas even high 80s). During gaming spikes occure, when drasticaly the frames lower for a second or few seconds. Then the frames go back to normal. I had like 2 longer spikes this evening when they were about 10 second long.

The temperature of my CPU is ~60c and GPU ~55c during gaming. I have installed Catalyst 13.2 drivers. Also the spikes dont go away at lower graphical settings. As the spikes occure using (render.perfoverlayvisible 1) in the game both the CPU and GPU graphics spike quite a lot.


My system is:

AMD phenom II x4 955 @stock
HD 7850 1GB @900/1200
3GB of DDR3 ram
asus m4a79xtd evo
W 7 64bit
@1280x1024 res

I dont have these problems in other games like far cry3, dota 2, d3 etc.
Could this problem be caused by my systems ram amount?

Help would be appreciated!

Matiss