I am playing at 1920x1080 and I also notice when I lower the settings the fps is still the same. I hope I don't have to return the gtx680. Don't want to spend too much upgrading the the motherboard and CPU..unless I have no choice
Thats a CPU Bottleneck for sure.
When you Lower or Higher your Setting and still don't see a Difference, then its CPU Bottleneck.
Best is to get i5.
As you cannot get FX series. They fit in AM3+ Socket.