GeForce GTX 580 3GB vs Radeon HD 7990

Intro

Compare all that to the Radeon HD 7990, which comes with clock speeds of 950 MHz on the GPU, and 1500 MHz on the 3072 MB of GDDR5 RAM. It features 2048 SPUs as well as 128 Texture Address Units and 32 ROPs.

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

In theory, the Radeon HD 7990 will be 199% faster than the GeForce GTX 580 3GB overall, because of its greater bandwidth. (explain)

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

Texel Rate

The Radeon HD 7990 will be a lot (approximately 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

The Radeon HD 7990 should be a lot (more or less 64%) faster with regards to AA than the GeForce GTX 580 3GB, and capable of handling higher screen resolutions better. (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 maximum amount of data (in units of megabytes per second) that can be transported over the external memory interface within a second. The number is calculated by multiplying the card's bus width by the speed of its memory. In the case of DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.