Radeon HD 4850 X2 1GB vs Radeon HD 6950 2GB

Intro

Compare all that to the Radeon HD 6950 2GB, which has a GPU core clock speed of 800 MHz, and 2048 MB of GDDR5 RAM set to run at 1250 MHz through a 256-bit bus. It also is comprised of 1408 SPUs, 88 TAUs, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6950 2GB		200 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 50 Watts (25%)

Memory Bandwidth

In theory, the Radeon HD 6950 2GB will be 26% faster than the Radeon HD 4850 X2 1GB overall, due to its higher data rate. (explain)

Radeon HD 6950 2GB		160000 MB/sec
Radeon HD 4850 X2 1GB		127104 MB/sec
	Difference: 32896 (26%)

Texel Rate

The Radeon HD 6950 2GB will be a lot (more or less 41%) faster with regards to texture filtering than the Radeon HD 4850 X2 1GB. (explain)

Radeon HD 6950 2GB		70400 Mtexels/sec
Radeon HD 4850 X2 1GB		50000 Mtexels/sec
	Difference: 20400 (41%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 6950 2GB is the winner, by far. (explain)

Radeon HD 6950 2GB		25600 Mpixels/sec
Radeon HD 4850 X2 1GB		20000 Mpixels/sec
	Difference: 5600 (28%)

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 maximum amount of data (counted in megabytes per second) that can be transported past the external memory interface in one second. The number is calculated by multiplying the card's bus width by its memory clock speed. In the case of DDR RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better 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 amount of texture map elements (texels) that can be processed in one second. This figure is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

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