BF3 Fps drops

Gaming
1

So i built my brother a mid range gaming pc a few weeks ago and it would run bf3 on ultra and 2xaa but now it just seems to want to give up on keeping stable frame rates. i have reinstalled drivers antivirus sofware put it some code that stopped it moderatly but now every so often it just goes from 40-60 frames on 64 man caspian border and just randomly drop down to 5-10 frames for about a second. I ran msi afterburner and his gpu is only running at 50-70% while playing bf3.

i3 3220

gtx660 gigabyte oc 

8gb gskill ripjaws

B75m-d3h

vp550

Any help?

Thanks in advance.

2

Uninstall the newest drivers from nvidia and find the ones that worked best for you because with my card I could barley playgmod 670" because of the new driver update 

3

whats the vram on the card? its possible in 64 man servers that a 1 gig card coupd peak on one of the bigger maps like that