Radeon HD 4850 X2 512MB vs Radeon HD 7950 3GB

Intro

Compare those specifications to the Radeon HD 7950 3GB, which has a GPU core clock speed of 800 MHz, and 3072 MB of GDDR5 RAM running at 1250 MHz through a 384-bit bus. It also is made up of 1792 Stream Processors, 112 TAUs, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7950 3GB		200 Watts
Radeon HD 4850 X2 512MB		250 Watts
	Difference: 50 Watts (25%)

Memory Bandwidth

The Radeon HD 7950 3GB should theoretically perform a lot faster than the Radeon HD 4850 X2 512MB in general. (explain)

Radeon HD 7950 3GB		240000 MB/sec
Radeon HD 4850 X2 512MB		127104 MB/sec
	Difference: 112896 (89%)

Texel Rate

The Radeon HD 7950 3GB is much (more or less 79%) better at texture filtering than the Radeon HD 4850 X2 512MB. (explain)

Radeon HD 7950 3GB		89600 Mtexels/sec
Radeon HD 4850 X2 512MB		50000 Mtexels/sec
	Difference: 39600 (79%)

Pixel Rate

The Radeon HD 7950 3GB is much (more or less 28%) faster with regards to AA than the Radeon HD 4850 X2 512MB, and will be able to handle higher resolutions while still performing well. (explain)

Radeon HD 7950 3GB		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 largest amount of information (measured in megabytes per second) that can be transferred past the external memory interface in one second. It's worked out by multiplying the card's interface width by the speed of its memory. If it uses DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum 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 better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly record to its 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 speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.