Radeon HD 3870 X2 1GB vs Radeon HD 6870

Intro

Compare all of that to the Radeon HD 6870, which features clock speeds of 900 MHz on the GPU, and 1050 MHz on the 1024 MB of GDDR5 RAM. It features 1120 SPUs as well as 56 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically, the Radeon HD 3870 X2 1GB should perform just a bit faster than the Radeon HD 6870 overall. (explain)

Radeon HD 3870 X2 1GB		144128 MB/sec
Radeon HD 6870		134400 MB/sec
	Difference: 9728 (7%)

Texel Rate

The Radeon HD 6870 will be much (about 91%) more effective at texture filtering than the Radeon HD 3870 X2 1GB. (explain)

Radeon HD 6870		50400 Mtexels/sec
Radeon HD 3870 X2 1GB		26400 Mtexels/sec
	Difference: 24000 (91%)

Pixel Rate

The Radeon HD 6870 will be a bit (approximately 9%) faster with regards to AA than the Radeon HD 3870 X2 1GB, and also should be able to handle higher screen resolutions without losing too much performance. (explain)

Radeon HD 6870		28800 Mpixels/sec
Radeon HD 3870 X2 1GB		26400 Mpixels/sec
	Difference: 2400 (9%)

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 (counted in megabytes per second) that can be moved over the external memory interface within a second. It is calculated by multiplying the bus width by its memory clock speed. If the card has DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels the video card could possibly write to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of 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 fill rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.