GeForce 9800 GX2 vs Radeon HD 6990

Intro

Compare those specs to the Radeon HD 6990, which features a GPU core clock speed of 830 MHz, and 2048 MB of GDDR5 RAM set to run at 1250 MHz through a 256-bit bus. It also is comprised of 1536 SPUs, 96 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 9800 GX2		197 Watts
Radeon HD 6990		375 Watts
	Difference: 178 Watts (90%)

Memory Bandwidth

Performance-wise, the Radeon HD 6990 should theoretically be a lot better than the GeForce 9800 GX2 in general. (explain)

Radeon HD 6990		320000 MB/sec
GeForce 9800 GX2		128000 MB/sec
	Difference: 192000 (150%)

Texel Rate

The Radeon HD 6990 will be a lot (about 108%) faster with regards to anisotropic filtering than the GeForce 9800 GX2. (explain)

Radeon HD 6990		159360 Mtexels/sec
GeForce 9800 GX2		76800 Mtexels/sec
	Difference: 82560 (108%)

Pixel Rate

The Radeon HD 6990 should be a lot (more or less 177%) better at full screen anti-aliasing than the GeForce 9800 GX2, and able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 6990		53120 Mpixels/sec
GeForce 9800 GX2		19200 Mpixels/sec
	Difference: 33920 (177%)

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 (measured in MB per second) that can be transported across the external memory interface within a second. It is calculated by multiplying the card's interface width by its memory speed. If it uses DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better 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 are applied per second. This is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The higher this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly write to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.