GeForce 9800 GX2 vs Radeon HD 7970

Intro

Compare those specs to the Radeon HD 7970, which has GPU clock speed of 925 MHz, and 3072 MB of GDDR5 RAM running at 1375 MHz through a 384-bit bus. It also is comprised of 2048 Stream Processors, 128 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 9800 GX2		197 Watts
Radeon HD 7970		250 Watts
	Difference: 53 Watts (27%)

Memory Bandwidth

As far as performance goes, the Radeon HD 7970 should in theory be a lot better than the GeForce 9800 GX2 overall. (explain)

Radeon HD 7970		264000 MB/sec
GeForce 9800 GX2		128000 MB/sec
	Difference: 136000 (106%)

Texel Rate

The Radeon HD 7970 should be much (about 54%) better at anisotropic filtering than the GeForce 9800 GX2. (explain)

Radeon HD 7970		118400 Mtexels/sec
GeForce 9800 GX2		76800 Mtexels/sec
	Difference: 41600 (54%)

Pixel Rate

The Radeon HD 7970 is quite a bit (more or less 54%) more effective at full screen anti-aliasing than the GeForce 9800 GX2, and also should be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 7970		29600 Mpixels/sec
GeForce 9800 GX2		19200 Mpixels/sec
	Difference: 10400 (54%)

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 transferred past the external memory interface in a second. It is calculated by multiplying the card's bus width by its memory clock speed. If the card has DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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