Upgrading A Four-year Old Gaming Rig

Hello all. Four+ years ago, I custom built a gaming rig, and for reasons that are not worth going into, it ended up packed in a garage for the last few years. I am bringing it out of mothballs, and trying to decide if it needs to be upgraded.

It will primarily be for gaming. I don’t typically play FPS games; instead I am more into the Dragon Age/Mass Effect genres. Thus, I need a rig that will play games with decent graphics, but I don’t need the absolute top-of-the-line specs. When I last used this computer, it utilized an Eyefinity setup, and I may want to do that again.

I have relatively limited funds these days (8-month old son, dontcha know), so I don’t want to pour money into this project for little or no gain.

Here are the specs…

Full-Sized gaming case with liquid cooling
AMD Phenom II X4 965 Black Edition Quad-Core CPU (3.8 Ghz. I believe I overclocked it to about 4.0)
8 GB DDR3-1600 RAM A-DATA Gaming Series
Dual ATI Radeon HD 5850 1GB Video Cards
Motherboard: Gigabyte GA-790FXTA-UD5 AMD
Windows 7 Pro
800 watt power supply

Any advice would be warmly appreciated!

–David

Power supply manufacturer and model?

Video card upgrade would be good choice if PSU is OK. Radeon R9 280 offers best bang for buck.