Sources: AMD, Anandtech [power, noise, temp. results]
quote: On the contrary, the Radeon HD 7770 does have very strong competition from the GeForce 560 (as well as the Radeon 6800 series).
quote: It also seems that the days of a mid-range product being in league with a previous generations high-end product has come to an end. The 7770 is still no match for Radeon 6970 or 5870.