Radeon HD 4870 X2 vs Radeon HD 6950

Intro

Compare that to the Radeon HD 6950, which features GPU clock speed of 800 MHz, and 1024 MB of GDDR5 memory running at 1250 MHz through a 256-bit bus. It also is made up of 1408 SPUs, 88 Texture Address Units, and 32 ROPs.

Display Graphs

Hide Graphs

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

The Radeon HD 4870 X2, in theory, 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 should be just a bit (approximately 17%) more effective at texture 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

If running with a high screen resolution is important to you, then the Radeon HD 6950 is superior to the Radeon HD 4870 X2, though only just barely. (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 max amount of data (measured in MB per second) that can be transferred over the external memory interface within a second. It's calculated by multiplying the card's interface width by the speed of its memory. In the case of DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of colour ROPs 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 output rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.