I would say 955. The 955 is 4 real cores while the FX-4100 is 2 modules that each have about 180% of dual core performance so not quite a quad in performance.
Plus if the FX-8150 barley outpaces the Phenom II X6, I doubt the FX-4100 would outpace the 955 at all.
but pII is 3.2ghz and fx4100 is 3.6,IN PAPER FX 4100 Wins
what about the motherboard boattleneck problem ?