NVIDIA GeForce GTX 660 Launch Review - PAGE 2

NVIDIA's new GK106 utilizes a full chip implementation, as well as retaining all of the key features included with the GeForce GTX 680 like NVIDIA's SMX architecture along with the new GPU Boost, which both provide an increase in overall performance. The GK106 is equipped with three Graphics Processing Clusters (GPCs). Each of the GPCs contains its own dedicated raster engine. The GTX 660 also features five next generation Streaming Multiprocessor (SMX) units for a total of 960 CUDA cores that handle the job of pixel, vertex, geometry shading and physx computations alongside the 80 Texture Units. These five SMX units are spread across the three GPCs.

Let's just say that if you were to compare the new GK106 to earlier GeForce GPUs you will find that the new Streaming Multiprocessors offer far more performance when it comes to shaders, textures and geometry processing. At the same time, Kepler's Streaming Multiprocessors use less power while offering twice the performance per watt of the previous generations DirectX 11 GeForce GPUs.

On the memory side of things we again see the use of mixed density memory modules through which NVIDIA is able to equip the GTX 660 with 2GB of memory versus 1.5GB. The GTX 660's memory controllers divide the memory into fragments of 512MB, thereby creating a 1.5GB frame buffer and 192-bit interface. This leaves 512MB accessible through additional memory transactions by the first memory controller at a 64-bit width, while allowing the GPU to utilize the the full 2GB of onboard memory.

NVIDIA's GTX 660 GPU Boost is a mixture of both hardware and software technology. GPU Boost works independently and without the need for game profiles to automatically adjust the GPU's clock speeds, increasing performance as needed. The GTX 660's base clock is set to 980MHz. This is the minimum speed that the base clock will operate while under TDP load, i.e. gaming. This is where the GPU Boost comes in; with a base clock of 980MHz, that leaves room for an additional increase in the base clock to up to 1084MHz or higher, as long as it remains within the predefined power envelope. NVIDIA's GTX 660 has an average power draw of 115W in non TDP programs. When the GTX 660 is overclocked and the power slider is set at 110%, the average power draw will be around 127W in non TDP programs.