alright so i just built a pc and my 7770 was defective. so i think im going to buy a better vga but im not sure which. i was thinking of a 7970 ghz, 7870 ghz or a xfire 6870 combo. i want the best results for around 300-400 dollars. im hoping my build will last at least 2 years at 1080p gaming on ultra. the 7970 is 470 but i would be will to chip out the extra 70 dollars if it is worth it. i thought a 6870 combo might be nice because there is 2 of them doing half the work but then again it will probably be buggier. my mobo has 1 pcie 3.0 and 1 pcie 2.0. what would you say. btw i am kind of a computer newb, so if i said anything stupid dont be too hard on me.
8gb 1600mhz ram
as rock z75 mobo
those are the important parts, so what help can you guys offer