AMD GAMING RIG

Hey guys! So as the post mentioned, my old PC is toasted, as in I am not willing to put more time into fixing, I will just sell parts and buy me a new puppy. My previous PC was a intel, I posted my issues with it on this thread but I was never able to find the issue, and techs locally couldn't...

Gigabyte 780 Ti (GV-N78TOC-3GD) [1085/7000] vs MSI 780Ti GAMING 3G (Twin Frozr) [1085/7000]. Which one is better? Btw, what difference between OC mode (1085 Ghz) and Gaming mode (1046 GHz) in MSI GPU? And one more question: how long 780 Ti could run games @ Ultra settings @ 1080p? 2-3 years...