EPTThe anthlon x4 620 is great but it has no large cache it only sets 512kb per core of cache, and depending on the game that can seriously kill your fps potential. A phenom ii x3 710 720 for the same ish price is more stable performance across all games. And rts games is one of those that are more likely to require a larger cache as it does more calculations per a fame then a normal game would.
I'd also suggest getting a corsair 650TX over the 520HX save you money and the 520 is not single rail.
I'd also suggest getting the 5770 it performs right now around the same as a 4870 but given time the drivers will improve and so will the 5770, it also has a whole list of features that the 4870 doesn't have.
Also why are you buying a WD blue 640go drive that is a corporate drive the 640 black is cheap and performs a ways better.
Green= eco friendly drives low power
blue = corporate which is still low power but not as low
black = performance
)
