Summary: AMD's new Radeon HD 7770 delivers a substantial improvement over the previous generation HD 5770. The HD 6770 was just a HD 5770 with a "6770" sticker slapped on it, so the upgrade has been overdue. Averaged over all our testing we see more than 20% higher performance from the reference clocked HD 7770 vs. the HD 5770. This puts the HD 7770 on the same performance level as NVIDIA's GeForce GTX 460, or a bit below the HD 6850.
Pros: 20% performance increase over last generation, Excellent energy efficiency, Overclocked out of the box, Extremely quiet, No power consumption increase despite overclock, Excellent GPU overclocking potential, Native full-size HDMI & DisplayPort output, Adds support for PCI-Express 3.0 and DirectX 11.1, Support for multiple independent audio streams
Cons: Price too high to be competitive, Lower memory OC potential than other cards, Memory overclock is small, CCC Overdrive limits too low, Voltage controller not very overclocker-friendly