Not much good has happened for either party since AMD purchased ATI. New chips from both sides of the fence have been late, run hot, and underperformed compared to the competition. Meanwhile, the combined company has posted staggering financial losses, causing many folks to wonder whether AMD could continue to hold up its end of the bargain as junior partner in the PC market's twin duopolies, for CPUs and graphics chips.

AMD certainly has its fair share of well-wishers, as underdogs often do. And a great many of them have been waiting with anticipation—you can almost hear them vibrating with excitement—for the Radeon HD 4800 series. The buzz has been building for weeks now. For the first time in quite a while, AMD would seem to have an unequivocal winner on its hands in this new GPU.

Our first peek at Radeon HD 4850 performance surely did nothing to quell the excitement. As I said then, the Radeon HD 4850 kicks more ass than a pair of donkeys in an MMA cage match. But that was only half of the story. What the Radeon HD 4870 tells us is that those donkeys are all out of bubble gum.Work on the chip code-named RV770 began two and a half years ago. AMD's design teams were, unusually, dispersed across six offices around the globe. Their common goal was to take the core elements of the underperforming R600 graphics processor and turn them into a much more efficient GPU. To make that happen, the engineers worked carefully on reducing the size of the various logic blocks on the chip without cutting out functionality. More efficient use of chip area allowed them to pack in more of everything, raising the peak capacity of the GPU in many ways. At the same time, they focused on making sure the GPU could more fully realize its potential by keeping key resources well fed and better managing the flow of data through the chip.

The fruit of their labors is a graphics processor whose elements look familiar, but whose performance and efficiency are revelations. Let's have a look at a 10,000-foot overview of the chip, and then we'll consider what makes it different.