Upgrade choice, cpu bottleneck

[chaon93]

I just upgraded my video card to a GTX 460 SE and i'm finding that there are still a lot of times where video games drop in frame rates a lot, particularly in larger firefights or when a lot is just going on. I'm assuming its because my older althlon 64 x2 5200+ is starting to have trouble keeping up but im not sure. If I do upgrade should i go phenom2 x6 or just go with a phenom2 x4 and spend the extra 50 on something else, like 4 more gb of ram

 

[chaon93]

Best answer selected by chaon93.