Radeon HD 4850 X2 512MB vs Radeon HD 7970

Intro

Compare all that to the Radeon HD 7970, which has a GPU core clock speed of 925 MHz, and 3072 MB of GDDR5 RAM set to run at 1375 MHz through a 384-bit bus. It also features 2048 SPUs, 128 TAUs, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Both cards have the same power consumption.

Memory Bandwidth

As far as performance goes, the Radeon HD 7970 should in theory be a lot superior to the Radeon HD 4850 X2 512MB in general. (explain)

Radeon HD 7970		264000 MB/sec
Radeon HD 4850 X2 512MB		127104 MB/sec
	Difference: 136896 (108%)

Texel Rate

The Radeon HD 7970 is much (about 137%) more effective at anisotropic filtering than the Radeon HD 4850 X2 512MB. (explain)

Radeon HD 7970		118400 Mtexels/sec
Radeon HD 4850 X2 512MB		50000 Mtexels/sec
	Difference: 68400 (137%)

Pixel Rate

The Radeon HD 7970 should be much (more or less 48%) more effective at full screen anti-aliasing than the Radeon HD 4850 X2 512MB, and should be able to handle higher resolutions without slowing down too much. (explain)

Radeon HD 7970		29600 Mpixels/sec
Radeon HD 4850 X2 512MB		20000 Mpixels/sec
	Difference: 9600 (48%)

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 max amount of information (measured in MB per second) that can be transported past the external memory interface in one second. The number is worked out by multiplying the card's bus width by its memory clock speed. If the card has DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed in one second. This figure is calculated by multiplying the total amount of texture units of the card by the core clock 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 number of pixels that the graphics chip can possibly record to the local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the the core 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 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 maximum fill rate.