GeForce GTX 280 vs Radeon HD 6990

Intro

Compare all of that to the Radeon HD 6990, which comes with clock speeds of 830 MHz on the GPU, and 1250 MHz on the 2048 MB of GDDR5 RAM. It features 1536 SPUs along with 96 Texture Address Units and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 280		236 Watts
Radeon HD 6990		375 Watts
	Difference: 139 Watts (59%)

Memory Bandwidth

In theory, the Radeon HD 6990 will be 126% faster than the GeForce GTX 280 in general, due to its greater bandwidth. (explain)

Radeon HD 6990		320000 MB/sec
GeForce GTX 280		141696 MB/sec
	Difference: 178304 (126%)

Texel Rate

The Radeon HD 6990 is much (about 231%) faster with regards to texture filtering than the GeForce GTX 280. (explain)

Radeon HD 6990		159360 Mtexels/sec
GeForce GTX 280		48160 Mtexels/sec
	Difference: 111200 (231%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 6990 is the winner, and very much so. (explain)

Radeon HD 6990		53120 Mpixels/sec
GeForce GTX 280		19264 Mpixels/sec
	Difference: 33856 (176%)

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 largest amount of data (counted in MB per second) that can be transported over the external memory interface within a second. The number is worked out by multiplying the card's interface width by its memory speed. If the card has DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly record to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.