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.
We have seen great overclocking potential from the AMD HD 7900 Series, and the HD 7700 Series is just like it. Overclocking the cards well beyond 1 GHz is quite easy. We reached between 1140 and 1180 MHz on the cards tested today. Memory overclocks well, too, resulting in a total real-life performance improvement of about 15%.
AMD's new generation of graphics processors has great power consumption: below 70W during typical gaming is a first for this performance class. Idle power consumption is also down, at 7 Watts now, which is great for users who spend most of their time with productivity and rarely game. Overall performance per Watt is leading our charts, only to be bested by AMD's other card released today, the HD 7750.
Gigabyte's new HD 7770 OC uses a custom heatsink by the company which we have seen on other cards before. It does a good job at keeping the card cool, but the noise levels seem a bit high. It seems to me that the fan control settings in BIOS are not optimized to match the cooler's new capabilities.
The card comes overclocked out of the box with a large clock speed increase of 10% on the GPU, which translates into a 7% performance increase, putting the card on the same performance level as GTX 465 or HD 5850. Additional overclocking potential was slim, other HD 7770 models gave us much better improvements here. Maybe our Gigabyte review sample ended up being a bad overclocker by luck of the draw, it's hard to say. Having such a large overclock out of the box is very nice for less experienced users all they will get the maximum out of their card without having to do any manual tweaking.
Overall the HD 7770 is a good product with lots of potential, if there weren't the sky high price. AMD's officially suggested retailer pricing is "starting at $159", which is where the Gigabyte HD 7770 OC is positioned. Cards like the HD 6850 ($135) and HD 6870 ($155) are faster, and give you much more bang for your buck, up to 30% more! In my opinion a more reasonable price for the HD 7770 would be below $130.