NVIDIA GeForce 6800 GT vs 6800 XT

There are two characteristics that affect the maximum pixel fillrate, the number of Raster Operations Pipelines (ROPs) and graphics clock. The GeForce 6800 GT has a very big advantage in this area, as it operates at higher rate and has twice as many ROPs (Raster Operations Pipelines). Better maximum pixel fill rate allows more pixels to be drawn on screen per second, which results in increased GPU performance, unless the card is limited by something else, such as texture mapping or memory bandwidth.

The GeForce 6800 GT graphics card has twice as many TMUs than the NVIDIA GeForce 6800 XT graphics card. Additionally, its graphics clock rate is higher, thus it has significantly higher texture fillrate. Better maximum texture fill rate means that the GPU can apply more textures and/or use more complex 3D effects for each textured picture element, which improves games visual appearance.

To speed up processing, the cards store 3D scene data, textures and intermediate data, used for image generation, in on-board memory. The video memory usually has much higher bandwidth than system RAM, and more bandwidth allows the card to run at higher display resolutions, use larger and more detailed textures, and apply more complex 3D effects and filters. Memory type, speed, and width of memory interface all affect the bandwidth value. Specifically, higher memory bandwidth of the GeForce 6800 GT graphics unit is a result of higher clocked memory of better kind.