Radeon HD 3870 X2 1GB vs Radeon HD 6950

Intro

Compare those specs to the Radeon HD 6950, which comes with GPU core speed of 800 MHz, and 1024 MB of GDDR5 memory set to run at 1250 MHz through a 256-bit bus. It also is comprised of 1408 Stream Processors, 88 TAUs, and 32 ROPs.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Memory Bandwidth

Performance-wise, the Radeon HD 6950 should in theory be a little bit superior to the Radeon HD 3870 X2 1GB in general. (explain)

Radeon HD 6950		160000 MB/sec
Radeon HD 3870 X2 1GB		144128 MB/sec
	Difference: 15872 (11%)

Texel Rate

The Radeon HD 6950 should be much (about 167%) better at anisotropic filtering than the Radeon HD 3870 X2 1GB. (explain)

Radeon HD 6950		70400 Mtexels/sec
Radeon HD 3870 X2 1GB		26400 Mtexels/sec
	Difference: 44000 (167%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 3870 X2 1GB is the winner, though not by far. (explain)

Radeon HD 3870 X2 1GB		26400 Mpixels/sec
Radeon HD 6950		25600 Mpixels/sec
	Difference: 800 (3%)

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 largest amount of information (counted in MB per second) that can be transported across the external memory interface in one second. It is calculated by multiplying the interface width by the speed of its memory. If it uses DDR RAM, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This is calculated by multiplying the total number of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines 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 is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.