GeForce 8800 GT 512MB vs Radeon HD 6990

Intro

Compare those specifications to the Radeon HD 6990, which uses a 40 nm design. AMD has set the core frequency at 830 MHz. The GDDR5 RAM is set to run at a speed of 1250 MHz on this particular card. It features 1536 SPUs as well as 96 Texture Address Units and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 8800 GT 512MB		105 Watts
Radeon HD 6990		375 Watts
	Difference: 270 Watts (257%)

Memory Bandwidth

The Radeon HD 6990, in theory, should perform a lot faster than the GeForce 8800 GT 512MB in general. (explain)

Radeon HD 6990		320000 MB/sec
GeForce 8800 GT 512MB		57600 MB/sec
	Difference: 262400 (456%)

Texel Rate

The Radeon HD 6990 is quite a bit (approximately 374%) faster with regards to texture filtering than the GeForce 8800 GT 512MB. (explain)

Radeon HD 6990		159360 Mtexels/sec
GeForce 8800 GT 512MB		33600 Mtexels/sec
	Difference: 125760 (374%)

Pixel Rate

The Radeon HD 6990 will be a lot (more or less 453%) faster with regards to FSAA than the GeForce 8800 GT 512MB, and capable of handling higher resolutions without slowing down too much. (explain)

Radeon HD 6990		53120 Mpixels/sec
GeForce 8800 GT 512MB		9600 Mpixels/sec
	Difference: 43520 (453%)

Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the max amount of data (in units of MB per second) that can be moved over the external memory interface within a second. It is worked out by multiplying the interface width by its memory clock speed. If the card has DDR type memory, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs 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 is also dependant on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.