Radeon HD 3870 X2 1GB vs Radeon HD 6950 2GB

Intro

Compare those specs to the Radeon HD 6950 2GB, which comes with a core clock frequency of 800 MHz and a GDDR5 memory frequency of 1250 MHz. It also uses a 256-bit bus, and uses a 40 nm design. It is made up of 1408 SPUs, 88 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 6950 2GB will be 11% quicker than the Radeon HD 3870 X2 1GB in general, due to its higher data rate. (explain)

Radeon HD 6950 2GB		160000 MB/sec
Radeon HD 3870 X2 1GB		144128 MB/sec
	Difference: 15872 (11%)

Texel Rate

The Radeon HD 6950 2GB will be quite a bit (approximately 167%) faster with regards to texture filtering than the Radeon HD 3870 X2 1GB. (explain)

Radeon HD 6950 2GB		70400 Mtexels/sec
Radeon HD 3870 X2 1GB		26400 Mtexels/sec
	Difference: 44000 (167%)

Pixel Rate

The Radeon HD 3870 X2 1GB is a bit (about 3%) more effective at full screen anti-aliasing than the Radeon HD 6950 2GB, and capable of handling higher screen resolutions without losing too much performance. (explain)

Radeon HD 3870 X2 1GB		26400 Mpixels/sec
Radeon HD 6950 2GB		25600 Mpixels/sec
	Difference: 800 (3%)

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 data (counted in MB per second) that can be transferred over the external memory interface within a second. It is worked out by multiplying the card's bus width by its memory speed. If the card has DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher 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 amount of texture map elements (texels) that are processed in one second. This figure is worked out by multiplying the total texture units by the core speed of the chip. The higher 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 a second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.