Gigabyte HD 7770 OC 1 GB @ techPowerUp
 

Gigabyte's HD 7770 OC comes with a massive clock improvement over the AMD reference design. Operating at 1100 MHz ensures that the card has a healthy performance advantage over other boards. Memory clock is also increased at 1250 MHz.

http://www.techpowerup.com/reviews/Gigabyte/HD_7770_OC/