I think that all the parts you selected are compatible and will work in that build. The CPU seems to be the bottleneck and the slowest choice. With those 2 480 video cards, why not chose an i-7 980X? It would be a benchmark record breaker. However, if I was building a system, I would only install one video card, probably an HD 5870 and use just 4 GB or RAM with an 1156 chipset.