I read something about Intel i3-2120 3,3GHz, and it's not bottlenecking my GPU.
Okay, i'm playing Bf3 with 1920x1080 resolution and high settings.
Can try turning down the settings or resolution a bit and see if it clears up. If it does, it could be you're just maxing the card out. BF3 is a pretty demanding game. When you say it does it sometimes, does it seem to do it on more maps other than others.