Radeon HD 4870 X2 vs Radeon HD 7950 3GB

Intro

Compare all of that to the Radeon HD 7950 3GB, which makes use of a 28 nm design. AMD has set the core speed at 800 MHz. The GDDR5 memory works at a frequency of 1250 MHz on this particular card. 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

In theory, the Radeon HD 7950 3GB should perform a bit faster than the Radeon HD 4870 X2 overall. (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 should be a lot (about 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 small bit (about 7%) faster with regards to AA than the Radeon HD 4870 X2, and also should be capable of handling higher resolutions without slowing down too much. (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: Bandwidth is the max amount of information (in units of MB per second) that can be moved past the external memory interface in one second. It is worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR type memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better 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 texture map elements (texels) that can be applied in one second. This is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The higher this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could 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 core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.