Radeon HD 4870 X2 vs Radeon HD 6870

Intro

Compare that to the Radeon HD 6870, which has core 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 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6870		151 Watts
Radeon HD 4870 X2		350 Watts
	Difference: 199 Watts (132%)

Memory Bandwidth

The Radeon HD 4870 X2 should in theory perform a lot faster than the Radeon HD 6870 overall. (explain)

Radeon HD 4870 X2		230400 MB/sec
Radeon HD 6870		134400 MB/sec
	Difference: 96000 (71%)

Texel Rate

The Radeon HD 4870 X2 is a bit (about 19%) faster with regards to anisotropic filtering than the Radeon HD 6870. (explain)

Radeon HD 4870 X2		60000 Mtexels/sec
Radeon HD 6870		50400 Mtexels/sec
	Difference: 9600 (19%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 6870 is the winner, not by a very large margin though. (explain)

Radeon HD 6870		28800 Mpixels/sec
Radeon HD 4870 X2		24000 Mpixels/sec
	Difference: 4800 (20%)

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 transported past the external memory interface in one second. It's worked out by multiplying the bus width by its memory speed. If it uses DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.