The reason I asked about your RAMs speed, AMD has *Sweet Spots* with the RAM dividers that allow you to run the sticks at stock speeds. As an example with DDR3 1333MHz, the sweet spot is a system clock of 250MHz. You simply drop the divider from stock 6.67 to 5.33
15 x 250MHz = 3.75GHz CPU
5.33 x 250MHz = 1333MHz RAMs
Enjoy your CPU -- it should not be holding you back much, if any.
Edit: I fergit ...
Leave your HT Link as close to 2000MHz as practical, and raise your IMC/NB at high as you can!
For each 10% in speed you increase your IMC/NB, memory bandwidth is increased 3-4% and latency is reduced 3-4%