Radeon HD 3870 X2 512MB vs Radeon HD 7950

Intro

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

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Performance-wise, the Radeon HD 7950 should in theory be much better than the Radeon HD 3870 X2 512MB in general. (explain)

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

Texel Rate

The Radeon HD 7950 is quite a bit (approximately 239%) more effective at anisotropic filtering than the Radeon HD 3870 X2 512MB. (explain)

Radeon HD 7950		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 the winner, but not by far. (explain)

Radeon HD 3870 X2 512MB		26400 Mpixels/sec
Radeon HD 7950		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: Memory bandwidth is the largest amount of data (in units of megabytes per second) that can be moved past the external memory interface within a second. It is worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR type RAM, the result should be multiplied by 2 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, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This figure is worked out by multiplying the total amount of texture units 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 processed in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. 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 get to the maximum fill rate.