GeForce 9800 GX2 vs Radeon HD 6990

Intro

Compare that to the Radeon HD 6990, which has a clock speed of 830 MHz and a GDDR5 memory frequency of 1250 MHz. It also features a 256-bit memory bus, and makes use of a 40 nm design. It is made up of 1536 SPUs, 96 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 6990		375 Watts
	Difference: 178 Watts (90%)

Memory Bandwidth

Performance-wise, the Radeon HD 6990 should in theory be much 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 should be much (more or less 108%) more effective at AF 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 much (about 177%) better at AA than the GeForce 9800 GX2, and also will be capable of handling higher screen resolutions without losing too much performance. (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: Bandwidth is the maximum amount of data (in units of megabytes per second) that can be transferred across the external memory interface in one second. It is worked out by multiplying the card's interface width by the speed of its memory. If it uses DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, 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 amount of texture map elements (texels) that can be processed in one second. This figure is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The better this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.