Gigabyte 7970 (GV-R797TO-3GD) [1100/6000] vs Gigabyte 290X (GV-R929XD5-4GD-B) [1000/5000] vs 780 Ti (GV-N78TOC-3GD) [1085/7000]. Which one is better @ 1080p (ULTRA Settings). And which GPU can be hold longest time for commfortable play @ 1080p ULTRA Settings? Sorry for my bad english