For several generations now, whenever a new Radeon GPU was making its debut, I have bugged AMD Graphics CTO Eric Demers about whatever features were missing compared to the competition. There have always been feature deficits, whether it be graphics-oriented capabilities like coverage sampled antialiasing and faster geometry processing or compute-focused capabilities like better scheduling, caching, and ECC protection. Each time, Demers has answered my questions about what's missing with quiet confidence, preaching the gospel of making the correct tradeoffs in each successive generation of products without compromising on architectural efficiency or time-to-market.
That confidence has seemed increasingly well founded as the years have progressed, in part because we often seem to be comparing what AMD is doing right now to what Nvidia will presumably be doing later. After all, AMD has been first to market with revamped GPU architectures based on new process tech for quite a few generations in a row. It hasn't hurt that, since the introduction of the Radeon HD 4800 series, AMD has been at least competitive with Nvidia's flagship chips in contemporary games, if not outright faster, while building substantially smaller, more efficient GPUs. Meanwhile, the firm has steadily ratcheted up the graphics- and compute-focused features in its new chips, gaining ground on Nvidia seemingly every step of the way.
With Tahiti and the Radeon HD 7970, AMD appears to have reached a very nice destination. In graphics terms, the Radeon HD 6970 and Cayman had very nearly achieved feature parity with the GF110. Tahiti moves AMD a few steps ahead on that front, though the changes aren't major. The biggest news there may be the improvements to tessellation performance. Tahiti may not have caught up to Nvidia entirely in geometry throughput, but it's fast enough now that no one is likely to notice the difference in any way that matters.
The more consequential changes in this GPU are primarily compute-related features, including caching, C++ support, ECC protection, and the revamped shader array. AMD has dedicated substantial space on this chip to things like SRAM and ECC support, and Tahiti looks poised to take on Nvidia in the nascent market for GPUs in the data center as a result. Nvidia has one heckuva head start in many ways, but AMD can make its case on several fronts, including comparable feature sets, superior power efficiency, and more delivered FLOPS.
Gamers looking for the fastest graphics card in the world can rest assured that, at least for a while, the Radeon HD 7970 is it. Our testing has shown that when you move beyond FPS averages and get picky about consistently smooth action via low frame latencies, the differences between the most expensive cards in the market, including the 7970 and the GeForce GTX 580, tend to shrink. What that means is you're not always likely to feel the difference between one card and the other while playing a game, even if the average frame rates look to be fairly far apart. One can't help but wonder, as a little green birdie pointed out to us, whether AMD's choice to dedicate lots of die space to compute-focused features while, say, staying with eight ROP partitions hasn't hampered the 7970's ability to take a larger lead in gaming performance. Still, the 7970 draws substantially less power than the GTX 580, and heck, we had to choose carefully and crank up the image quality in order to make sure our suite of current games would be clearly performance limited on these cards. The Radeon HD 7970 ticks all of the right boxes, too, from PCIe 3.0 to video encoding to DirectX 11.1 and so on. For the time being, it's clearly the finest single-GPU video card in the world, and as such, it's earned a TR Editor's Choice award.