GeForce GTX 660 vs Radeon HD 6790

Intro

The GeForce GTX 660 comes with core speeds of 980 MHz on the GPU, and 1502 MHz on the 2048 MB of GDDR5 memory. It features 960 SPUs along with 80 Texture Address Units and 24 Rasterization Operator Units.

Compare that to the Radeon HD 6790, which has a GPU core clock speed of 840 MHz, and 1024 MB of GDDR5 RAM set to run at 1050 MHz through a 256-bit bus. It also features 800 SPUs, 40 Texture Address Units, and 16 Raster Operation Units.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the max amount of information (in units of megabytes per second) that can be moved over the external memory interface within a second. The number is worked out by multiplying the card's bus width by the speed of its memory. If it uses DDR memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This figure is worked out by multiplying the total texture units by the core speed of the chip. The higher this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.