Radeon HD 4870 X2 vs Radeon HD 6950

Intro

Compare that to the Radeon HD 6950, which uses a 40 nm design. AMD has clocked the core frequency at 800 MHz. The GDDR5 memory is set to run at a speed of 1250 MHz on this card. It features 1408 SPUs as well as 88 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6950		200 Watts
Radeon HD 4870 X2		350 Watts
	Difference: 150 Watts (75%)

Memory Bandwidth

Theoretically, the Radeon HD 4870 X2 should perform quite a bit faster than the Radeon HD 6950 overall. (explain)

Radeon HD 4870 X2		230400 MB/sec
Radeon HD 6950		160000 MB/sec
	Difference: 70400 (44%)

Texel Rate

The Radeon HD 6950 is a bit (about 17%) more effective at anisotropic filtering than the Radeon HD 4870 X2. (explain)

Radeon HD 6950		70400 Mtexels/sec
Radeon HD 4870 X2		60000 Mtexels/sec
	Difference: 10400 (17%)

Pixel Rate

The Radeon HD 6950 is a bit (about 7%) more effective at FSAA than the Radeon HD 4870 X2, and also capable of handling higher resolutions more effectively. (explain)

Radeon HD 6950		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 maximum amount of information (in units of MB per second) that can be transported over the external memory interface within a second. It's worked out by multiplying the card's bus width by its memory clock speed. If the card has DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better 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 applied per second. This number is calculated by multiplying the total amount of texture units of the card 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 processed in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.