Radeon HD 4850 X2 1GB vs Radeon HD 7950 3GB

Intro

Compare all of that to the Radeon HD 7950 3GB, which features a core clock speed of 800 MHz and a GDDR5 memory frequency of 1250 MHz. It also features a 384-bit bus, and uses a 28 nm design. It features 1792 SPUs, 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 3GB		200 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 50 Watts (25%)

Memory Bandwidth

Performance-wise, the Radeon HD 7950 3GB should theoretically be a lot superior to the Radeon HD 4850 X2 1GB in general. (explain)

Radeon HD 7950 3GB		240000 MB/sec
Radeon HD 4850 X2 1GB		127104 MB/sec
	Difference: 112896 (89%)

Texel Rate

The Radeon HD 7950 3GB will be much (more or less 79%) better at anisotropic filtering than the Radeon HD 4850 X2 1GB. (explain)

Radeon HD 7950 3GB		89600 Mtexels/sec
Radeon HD 4850 X2 1GB		50000 Mtexels/sec
	Difference: 39600 (79%)

Pixel Rate

The Radeon HD 7950 3GB should be quite a bit (approximately 28%) more effective at AA than the Radeon HD 4850 X2 1GB, and also able to handle higher resolutions more effectively. (explain)

Radeon HD 7950 3GB		25600 Mpixels/sec
Radeon HD 4850 X2 1GB		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 maximum amount of data (in units of MB per second) that can be transported across the external memory interface in one second. The number is calculated by multiplying the card's bus width by the speed of its memory. If it uses DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed per second. This number is worked out by multiplying the total amount of texture units by the core speed of the chip. The better this number, the better the 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 number of pixels that the graphics chip can possibly record to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units by the the core clock speed. 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 quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.