GeForce GTX 280 vs Radeon HD 6990

Intro

Compare all of that to the Radeon HD 6990, which comes with GPU clock speed of 830 MHz, and 2048 MB of GDDR5 memory running at 1250 MHz through a 256-bit bus. It also features 1536 Stream Processors, 96 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 280		236 Watts
Radeon HD 6990		375 Watts
	Difference: 139 Watts (59%)

Memory Bandwidth

In theory, the Radeon HD 6990 will be 126% quicker than the GeForce GTX 280 in general, due to its greater bandwidth. (explain)

Radeon HD 6990		320000 MB/sec
GeForce GTX 280		141696 MB/sec
	Difference: 178304 (126%)

Texel Rate

The Radeon HD 6990 should be quite a bit (approximately 231%) more effective at anisotropic filtering than the GeForce GTX 280. (explain)

Radeon HD 6990		159360 Mtexels/sec
GeForce GTX 280		48160 Mtexels/sec
	Difference: 111200 (231%)

Pixel Rate

The Radeon HD 6990 should be much (about 176%) more effective at FSAA than the GeForce GTX 280, and should be able to handle higher screen resolutions more effectively. (explain)

Radeon HD 6990		53120 Mpixels/sec
GeForce GTX 280		19264 Mpixels/sec
	Difference: 33856 (176%)

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 (measured in megabytes per second) that can be transferred over the external memory interface in a second. The number is calculated by multiplying the card's interface width by its memory speed. If the card has DDR RAM, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the better 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 applied per second. This figure is calculated by multiplying the total number 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 in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.