Radeon HD 4870 X2 vs Radeon HD 7950 3GB

Intro

Compare those specifications to the Radeon HD 7950 3GB, which has clock speeds of 800 MHz on the GPU, and 1250 MHz on the 3072 MB of GDDR5 RAM. It features 1792 SPUs as well as 112 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7950 3GB		200 Watts
Radeon HD 4870 X2		350 Watts
	Difference: 150 Watts (75%)

Memory Bandwidth

The Radeon HD 7950 3GB, in theory, should perform a small bit faster than the Radeon HD 4870 X2 in general. (explain)

Radeon HD 7950 3GB		240000 MB/sec
Radeon HD 4870 X2		230400 MB/sec
	Difference: 9600 (4%)

Texel Rate

The Radeon HD 7950 3GB will be much (approximately 49%) more effective at AF than the Radeon HD 4870 X2. (explain)

Radeon HD 7950 3GB		89600 Mtexels/sec
Radeon HD 4870 X2		60000 Mtexels/sec
	Difference: 29600 (49%)

Pixel Rate

The Radeon HD 7950 3GB should be a bit (more or less 7%) better at full screen anti-aliasing than the Radeon HD 4870 X2, and should be able to handle higher resolutions more effectively. (explain)

Radeon HD 7950 3GB		25600 Mpixels/sec
Radeon HD 4870 X2		24000 Mpixels/sec
	Difference: 1600 (7%)

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 across the external memory interface in a second. It is worked out by multiplying the bus width by its memory speed. If the card has DDR memory, it must be multiplied by 2 once again. If it uses 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 higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed per second. This is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.