Radeon HD 3870 X2 1GB vs Radeon HD 7970

Intro

Compare all of that to the Radeon HD 7970, which makes use of a 28 nm design. AMD has set the core speed at 925 MHz. The GDDR5 memory runs at a speed of 1375 MHz on this specific model. It features 2048 SPUs as well as 128 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 7970 should be much faster than the Radeon HD 3870 X2 1GB overall. (explain)

Radeon HD 7970		264000 MB/sec
Radeon HD 3870 X2 1GB		144128 MB/sec
	Difference: 119872 (83%)

Texel Rate

The Radeon HD 7970 is quite a bit (more or less 348%) better at anisotropic filtering than the Radeon HD 3870 X2 1GB. (explain)

Radeon HD 7970		118400 Mtexels/sec
Radeon HD 3870 X2 1GB		26400 Mtexels/sec
	Difference: 92000 (348%)

Pixel Rate

The Radeon HD 7970 will be a little bit (approximately 12%) faster with regards to AA than the Radeon HD 3870 X2 1GB, and will be capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 7970		29600 Mpixels/sec
Radeon HD 3870 X2 1GB		26400 Mpixels/sec
	Difference: 3200 (12%)

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 (in units of megabytes per second) that can be transferred over the external memory interface in a second. It is worked out by multiplying the card's bus width by its memory clock speed. If the card has DDR type memory, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This number is calculated by multiplying the total texture units of the card 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 a second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly write to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.