Get the E5-1620 CPU instead of the 1607. The 1607 doesn't have TurboBoost and is fixed at 3.0 GHz. The 1620 is a 3.6 GHz CPU with a 3.8 GHz TurboBoost mode. Hyperthreading, too.
(Why do people insist on picking the slowest CPU available in expensive workstations? It makes NO SENSE!)
You might want to look in the Administration forum, which is where most of the good discussions on hardware live. You might also want to ask this question there, after you have read through the relevant existing threads. Look especially at the latest thread from Charles Culp, I think it is his May suggestions.