Need help deciding GPU for A8 5600k

Hey guys, I have been researching cards for days and can't decide which card. I have looked at the radeon 7770 cards. Now I'm looking at the 6670 to do dual graphics. I'm so confused what to do if someone could give me some good advice, it would be appreciated.

It's actually fairly difficult to find a direct comparison, but personally, I'd go for a 7770, though if you can afford it, a 1GB 7850 would be even better.

The thing with Dual Graphics (or any crossfire configuration) is that it is a mixed bag. Even more so if the GPU's are slower, such as with 7660D and a 6670. Looking at some of the Dual-Graphics benches, it can range from actually [u][i]decreasing[/i][/u] overall performance, to a moderate increase (65%). sometimes, it may not do anything at all.

http://www.xbitlabs.com/articles/graphics/display/amd-trinity-graphics_9.html#sect0

It's a nice upgrade if you can't afford anything else, but it's usually better to have a faster GPU over two slower GPU's in Crossfire/SLI, and that really applies to anywhere on the spectrum of GPU performance.