GeForce 9800 GX2 vs Radeon HD 7950

Intro

Compare those specifications to the Radeon HD 7950, which features a clock frequency of 800 MHz and a GDDR5 memory speed of 1250 MHz. It also makes use of a 384-bit memory bus, and uses a 28 nm design. It is comprised of 1792 SPUs, 112 TAUs, 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 7950		200 Watts
	Difference: 3 Watts (2%)

Memory Bandwidth

Theoretically, the Radeon HD 7950 should perform much faster than the GeForce 9800 GX2 in general. (explain)

Radeon HD 7950		240000 MB/sec
GeForce 9800 GX2		128000 MB/sec
	Difference: 112000 (88%)

Texel Rate

The Radeon HD 7950 is a small bit (about 17%) more effective at AF than the GeForce 9800 GX2. (explain)

Radeon HD 7950		89600 Mtexels/sec
GeForce 9800 GX2		76800 Mtexels/sec
	Difference: 12800 (17%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 7950 is the winner, and very much so. (explain)

Radeon HD 7950		25600 Mpixels/sec
GeForce 9800 GX2		19200 Mpixels/sec
	Difference: 6400 (33%)

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

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called 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, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.