Radeon HD 6950 2GB vs Radeon HD 6990

Intro

Compare those specs to the Radeon HD 6990, which features core speeds of 830 MHz on the GPU, and 1250 MHz on the 2048 MB of GDDR5 RAM. It features 1536 SPUs along with 96 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6950 2GB		200 Watts
Radeon HD 6990		375 Watts
	Difference: 175 Watts (88%)

Memory Bandwidth

As far as performance goes, the Radeon HD 6990 should in theory be a lot better than the Radeon HD 6950 2GB in general. (explain)

Radeon HD 6990		320000 MB/sec
Radeon HD 6950 2GB		160000 MB/sec
	Difference: 160000 (100%)

Texel Rate

The Radeon HD 6990 will be quite a bit (about 126%) better at anisotropic filtering than the Radeon HD 6950 2GB. (explain)

Radeon HD 6990		159360 Mtexels/sec
Radeon HD 6950 2GB		70400 Mtexels/sec
	Difference: 88960 (126%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 6990 is the winner, by a large margin. (explain)

Radeon HD 6990		53120 Mpixels/sec
Radeon HD 6950 2GB		25600 Mpixels/sec
	Difference: 27520 (108%)

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 (counted in MB per second) that can be transported across the external memory interface in one second. It is worked out by multiplying the card's bus width by its memory speed. If it uses DDR type memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The better this number, the better the 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 number of pixels the video card can possibly record to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs 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 output rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.