Radeon HD 4850 X2 512MB vs Radeon HD 7970

Intro

Compare those specifications to the Radeon HD 7970, which makes use of a 28 nm design. AMD has clocked the core frequency at 925 MHz. The GDDR5 RAM works at a frequency 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

Both cards have the same power consumption.

Memory Bandwidth

Theoretically speaking, the Radeon HD 7970 is 108% quicker than the Radeon HD 4850 X2 512MB overall, due to its higher bandwidth. (explain)

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

Texel Rate

The Radeon HD 7970 will be a lot (more or less 137%) more effective at AF 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 is a lot (more or less 48%) better at full screen anti-aliasing than the Radeon HD 4850 X2 512MB, and also able to handle higher screen resolutions more effectively. (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 largest amount of information (counted in MB per second) that can be moved over the external memory interface in one second. It's calculated by multiplying the card's bus width by its memory clock speed. If the card has DDR type memory, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also called 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, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.