GeForce 9800 GX2 vs Radeon HD 7990

Intro

Compare all of that to the Radeon HD 7990, which features clock speeds of 950 MHz on the GPU, and 1500 MHz on the 3072 MB of GDDR5 memory. It features 2048 SPUs along with 128 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 9800 GX2		197 Watts
Radeon HD 7990		375 Watts
	Difference: 178 Watts (90%)

Memory Bandwidth

The Radeon HD 7990 should theoretically be quite a bit faster than the GeForce 9800 GX2 in general. (explain)

Radeon HD 7990		576000 MB/sec
GeForce 9800 GX2		128000 MB/sec
	Difference: 448000 (350%)

Texel Rate

The Radeon HD 7990 will be a lot (more or less 217%) better at AF than the GeForce 9800 GX2. (explain)

Radeon HD 7990		243200 Mtexels/sec
GeForce 9800 GX2		76800 Mtexels/sec
	Difference: 166400 (217%)

Pixel Rate

The Radeon HD 7990 is a lot (approximately 217%) more effective at anti-aliasing than the GeForce 9800 GX2, and should be capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 7990		60800 Mpixels/sec
GeForce 9800 GX2		19200 Mpixels/sec
	Difference: 41600 (217%)

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 (in units of megabytes per second) that can be transported past the external memory interface within a second. It's worked out by multiplying the interface width by its memory clock speed. If it uses DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.