chromos

is arma using more than 2gb ram at this moment? this could trigger paging and cause lags

-malloc=system gave me 90-99% gpuload and a performance boost even in mp. thx

fps got actually a little bit better for me. problem is that from time to time fps drop to 0 and cpu usage as well. it stays like that for 10sec and goes back to normal

I had exactly the same problem. And was able to fix it by replacing a dll in the battle-eye folder :) Just download the new dll battleye.com/download.html. I selected the the 1.62 dll which was about 30kb bigger than the one in the folder(\Arma 2 Operation Arrowhead\Expansion\BattlEye). First time I got a smooth experience. good luck