Radeon HD 3870 512MB vs Radeon HD 6950 2GB

Intro

Compare all that to the Radeon HD 6950 2GB, which comes with core clock speeds of 800 MHz on the GPU, and 1250 MHz on the 2048 MB of GDDR5 memory. It features 1408 SPUs as well as 88 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 512MB		106 Watts
Radeon HD 6950 2GB		200 Watts
	Difference: 94 Watts (89%)

Memory Bandwidth

In theory, the Radeon HD 6950 2GB will be 178% quicker than the Radeon HD 3870 512MB in general, due to its greater bandwidth. (explain)

Radeon HD 6950 2GB		160000 MB/sec
Radeon HD 3870 512MB		57600 MB/sec
	Difference: 102400 (178%)

Texel Rate

The Radeon HD 6950 2GB will be quite a bit (more or less 468%) more effective at AF than the Radeon HD 3870 512MB. (explain)

Radeon HD 6950 2GB		70400 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 58000 (468%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 6950 2GB is the winner, by a large margin. (explain)

Radeon HD 6950 2GB		25600 Mpixels/sec
Radeon HD 3870 512MB		12400 Mpixels/sec
	Difference: 13200 (106%)

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.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the maximum amount of data (counted in MB per second) that can be transferred over the external memory interface in one second. It is worked out by multiplying the card's interface width by its memory clock speed. If the card has DDR memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, 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 texture map elements (texels) that can be processed in one second. This is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The better the texel rate, 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 most pixels that the graphics card can possibly write to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.