Radeon HD 4850 X2 512MB vs Radeon HD 7950

Intro

Compare those specifications to the Radeon HD 7950, which features clock speeds of 800 MHz on the GPU, and 1250 MHz on the 1536 MB of GDDR5 RAM. It features 1792 SPUs as well as 112 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7950		200 Watts
Radeon HD 4850 X2 512MB		250 Watts
	Difference: 50 Watts (25%)

Memory Bandwidth

In theory, the Radeon HD 7950 should be quite a bit faster than the Radeon HD 4850 X2 512MB in general. (explain)

Radeon HD 7950		240000 MB/sec
Radeon HD 4850 X2 512MB		127104 MB/sec
	Difference: 112896 (89%)

Texel Rate

The Radeon HD 7950 is much (more or less 79%) better at texture filtering than the Radeon HD 4850 X2 512MB. (explain)

Radeon HD 7950		89600 Mtexels/sec
Radeon HD 4850 X2 512MB		50000 Mtexels/sec
	Difference: 39600 (79%)

Pixel Rate

The Radeon HD 7950 should be a lot (approximately 28%) better at full screen anti-aliasing than the Radeon HD 4850 X2 512MB, and able to handle higher resolutions more effectively. (explain)

Radeon HD 7950		25600 Mpixels/sec
Radeon HD 4850 X2 512MB		20000 Mpixels/sec
	Difference: 5600 (28%)

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 (measured in megabytes 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 the speed of its memory. If the card has DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's 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 amount of texture map elements (texels) that are processed in one second. This figure is worked out by multiplying the total texture units by the core clock speed of the chip. The higher the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of colour ROPs by the clock 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 fill rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.