Hello i want to upgrade my gpu. I have 4gbs of ddr3 ram and AMD Athlon II X4 640 cpu and a 600 watt corsair so power is not a problem . Can someone please tell me whats a new gpu i could get that can run bf3 on at least high. (i dont need a gpu to run ultra i am fine with high or medium settings). A gpu were i can get more that 40 fps constant would be nice for bf3. I am only running on a single "21" monitor and not going to overclock. Please someone with experience could tell me that has this cpu.