Short and sweet version?
Stay with the 920DO unless you are using 2stage or LN2.
I am using a sweet little single stage and own a golden w3580 (5.1GHz @ 1.45vc)
and gain nothing over my 920do because of wattage rating of a single stage (-45c @ 250w).
If anything, watch the Clarksdale as I think that will make a bigger difference in gaming/benching than the Gulftown. Merry Christmas and GL.