GeForce 8800 GTS (G80) 640MB vs Radeon HD 7870

Intro

The GeForce 8800 GTS (G80) 640MB makes use of a 90 nm design. nVidia has set the core frequency at 513 MHz. The GDDR3 memory is set to run at a speed of 792 MHz on this particular model. It features 96 SPUs as well as 48 Texture Address Units and 20 Rasterization Operator Units.

Compare those specifications to the Radeon HD 7870, which has a clock speed of 1000 MHz and a GDDR5 memory frequency of 1200 MHz. It also features a 256-bit bus, and uses a 28 nm design. It features 1280 SPUs, 80 TAUs, and 32 ROPs.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the largest amount of information (in units of megabytes per second) that can be moved past the external memory interface in a second. It's calculated by multiplying the bus width by its memory clock speed. If the card has DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.