Radeon HD 3870 X2 512MB vs Radeon HD 7950 3GB

Intro

Compare those specs to the Radeon HD 7950 3GB, which comes with a core clock frequency of 800 MHz and a GDDR5 memory speed of 1250 MHz. It also uses a 384-bit memory bus, and uses a 28 nm design. It is comprised of 1792 SPUs, 112 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 7950 3GB should in theory be a lot faster than the Radeon HD 3870 X2 512MB overall. (explain)

Radeon HD 7950 3GB		240000 MB/sec
Radeon HD 3870 X2 512MB		115200 MB/sec
	Difference: 124800 (108%)

Texel Rate

The Radeon HD 7950 3GB is much (approximately 239%) more effective at texture filtering than the Radeon HD 3870 X2 512MB. (explain)

Radeon HD 7950 3GB		89600 Mtexels/sec
Radeon HD 3870 X2 512MB		26400 Mtexels/sec
	Difference: 63200 (239%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 3870 X2 512MB is a better choice, though not by far. (explain)

Radeon HD 3870 X2 512MB		26400 Mpixels/sec
Radeon HD 7950 3GB		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 maximum amount of information (in units of megabytes per second) that can be transported past the external memory interface in a second. It's calculated by multiplying the card's bus width by its memory speed. In the case of DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly write to its local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.