Well really any 4 core processor will do, the 955 does overclock better and is a little bit better than the athlon. But the 955 is costs more because it overclocks better and it has a L3 cache (which helps but doesnt make that much of a difference) but if I had to choose I would chose your first option. Both quad cores are good but if I had to choose between a 5850 and a 5770, I would definitely choose the 5850.