GeForce GTX 580 3GB vs Radeon HD 7990

Intro

Compare all of that to the Radeon HD 7990, which has GPU clock speed of 950 MHz, and 3072 MB of GDDR5 RAM set to run at 1500 MHz through a 384-bit bus. It also is comprised of 2048 Stream Processors, 128 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 580 3GB		244 Watts
Radeon HD 7990		375 Watts
	Difference: 131 Watts (54%)

Memory Bandwidth

The Radeon HD 7990 should in theory perform much faster than the GeForce GTX 580 3GB overall. (explain)

Radeon HD 7990		576000 MB/sec
GeForce GTX 580 3GB		192384 MB/sec
	Difference: 383616 (199%)

Texel Rate

The Radeon HD 7990 should be quite a bit (about 392%) faster with regards to texture filtering than the GeForce GTX 580 3GB. (explain)

Radeon HD 7990		243200 Mtexels/sec
GeForce GTX 580 3GB		49408 Mtexels/sec
	Difference: 193792 (392%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 7990 is the winner, by far. (explain)

Radeon HD 7990		60800 Mpixels/sec
GeForce GTX 580 3GB		37056 Mpixels/sec
	Difference: 23744 (64%)

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: Bandwidth is the largest amount of data (counted in megabytes per second) that can be transferred past the external memory interface in one second. It is calculated by multiplying the card's bus width by its memory clock speed. If it uses DDR type RAM, the result should be multiplied by 2 once again. If 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 higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied in one second. This is calculated by multiplying the total number of texture units by the core speed of the chip. The higher this number, the better the card will be at 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 chip could possibly record to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.