Radeon HD 4870 X2 vs Radeon HD 6750

Intro

Compare those specs to the Radeon HD 6750, which features GPU clock speed of 725 MHz, and 512 MB of GDDR5 memory set to run at 1000 MHz through a 128-bit bus. It also features 720 SPUs, 36 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6750		86 Watts
Radeon HD 4870 X2		350 Watts
	Difference: 264 Watts (307%)

Memory Bandwidth

Performance-wise, the Radeon HD 4870 X2 should in theory be much better than the Radeon HD 6750 overall. (explain)

Radeon HD 4870 X2		230400 MB/sec
Radeon HD 6750		64000 MB/sec
	Difference: 166400 (260%)

Texel Rate

The Radeon HD 4870 X2 should be quite a bit (approximately 130%) more effective at texture filtering than the Radeon HD 6750. (explain)

Radeon HD 4870 X2		60000 Mtexels/sec
Radeon HD 6750		26100 Mtexels/sec
	Difference: 33900 (130%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 4870 X2 is a better choice, by a large margin. (explain)

Radeon HD 4870 X2		24000 Mpixels/sec
Radeon HD 6750		11600 Mpixels/sec
	Difference: 12400 (107%)

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 across the external memory interface within a second. The number is calculated by multiplying the interface width by its memory clock speed. If it uses DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This is calculated by multiplying the total number of texture units 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 in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly record to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.