Currently I have been running windowed at 1920x1080 with most settings on standard to high. I know shadows was turned down and no DoF or Ambient Occlusion. Game runs at 50-60 FPS most of the time and it doesn't tax a single core over 50% and the net CPU usage is about 25%.

Come to think of it, I believe I was having the same issues 6 months ago before I upgraded. Perhaps it is voltages as you mentioned. I just bumped my RAM voltage up and will look at NB/SB voltage suggestions for this board.

I'm downloading PC Mark for the stress testing.