Radeon HD 4850 X2 512MB vs Radeon HD 7950

Intro

Compare those specs to the Radeon HD 7950, which comes with core clock speeds of 800 MHz on the GPU, and 1250 MHz on the 1536 MB of GDDR5 memory. It features 1792 SPUs along with 112 Texture Address Units 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

The Radeon HD 7950 should theoretically perform much 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 will be a lot (approximately 79%) faster with regards to AF 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 is quite a bit (about 28%) better at FSAA than the Radeon HD 4850 X2 512MB, and able to handle higher resolutions better. (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: Bandwidth is the largest amount of information (in units of megabytes per second) that can be transported across the external memory interface within a second. The number is calculated by multiplying the card's bus width by its memory speed. If the card has DDR type RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.