So here's this "new" graphics card... called 7770. I made a quick comparison between 2 reliable brands on their overclocked versions, of this card. Even though HD 7770 has worse specifications than its predecessor HD 6770, it consumes less power and it performs way better than HD 6770. It performs even better than 6850 (i'm talking about OC 7770 vs stock 6850)... Personally I'd stick with XFX due to their AWESOME support and in this case, better performance at lower temperatures.
XFX vs. Sapphire HD 7770
Check the video, enjoy and subscribe.