Some of the most noticeable changes here are found in the GTX 680’s clock speeds. On paper this should lead to a 50% reduction in tessellation performance but the fixed function stages of Kepler have received a thorough facelift, making them substantially more powerful than those in previous generations. We can also see that NVIDIA has halved the PolyMorph Engine count. On the other hand, the quantity of ROPs has been dropped to 32 but as with many things in the Kepler architecture, the interaction between certain processing stages and these units has been refined, resulting in better throughput. It boasts 1536 CUDA cores –a threefold increase over the GTX 580- while the texture units have been doubled to 128, matching the HD 7970’s layout. More importantly, NVIDIA’s initial offering GK104 / GTX 680 is smaller and more efficient than AMD’s own Tahiti XT.įor the time being the GTX 680 will occupy the flagship spot in NVIDIA’s lineup and with good reason. In many ways Kepler can be considered a kind of “Fermi 2.0” since it still uses many of the same building blocks as its predecessor but as we will see on the upcoming pages, nearly every one of the rendering pipeline’s features have been augmented in some way. You see, unlike AMD, NVIDIA already had the solid foundation of an existing DX11 architecture to build upon and was able to focus upon rendering efficiency and performance per watt this time around. Most of the time, the architectural teams have a good idea of directionality but there’s always a significant amount of risk when it comes to releasing a new GPU core.Īt its heart Kepler was conceived as a way to further refine a DirectX 11 and HPC centric approach that began with Fermi. As they say, Rome wasn’t built in a day but in the GPU world “guestimates” are a way of life because no one really knows exactly where the market (or the competition) will be in a half decade's time. NVIDIA's newest Kepler architecture is a prime example of this the core that lies within the GeForce GTX 680's began its life as a rough schematic about five years ago.
Unbeknownst to many, the design process of modern GPU architectures is a long, drawn out process that involves hundreds of engineers, thousands of software architects and a healthy dose of assumption.