Here I go again asking questions. I'm a student and I find it hard to stretch my budget easily. The best upgrade I can do is a new power supply and either a 6850/6870. The reason I'm getting a new power supply its because I really know mine isn't good. This build is like years ago and the power supply is degrading and besides newer power supplies have better efficiency. So is it alright if I go for a Gigabyte 6850 Windforce? Just wondering. If not I might just go for a 6870 Non Reference Sapphire. And a XFX 650W power supply.