The Radeon HD 5770 was a runaway success for AMD. It garnered huge market share with it's solid performance, mainstream-target price, and introduction of the Eyefinity ecosystem at an attainable price point. Within the generation, it ended up being one of the most popular video cards on the market.
Back in the summer of 2010, I reviewed the Radeon HD 5770 and 5750. In my conclusion I wrote, "The 5770 is really the tipping point in the ATI Radeon HD 5000-series. It performs quite well in a single widescreen environment, and there are instances where it performs admirably in Eyefinity. If you frequently play older titles that aren't shader intensive, such as anything based on the Source engine (Half-Life 2, Team Fortress 2, Left4Dead), then the 5770 could well serve you in an Eyefinity environment. Even newer titles such as Batman and Dirt 2 can easily hit 30fps in Eyefinity."
Fast forward two generations, and we're now at the Radeon HD 7770. There really wasn't a Radeon HD 6770 - it was just a rebadged 5770 originally intended for OEMs. Games have come a long way in the last two years, with greater adoption of DX11 and advanced features such as tessellation. Has the "mainstream" offering from AMD kept pace with the times?