Radeon HD 3870 1GB vs Radeon HD 6750 1GB

Intro

Compare all that to the Radeon HD 6750 1GB, which has a GPU core clock speed of 725 MHz, and 1024 MB of GDDR5 memory set to run at 1000 MHz through a 128-bit bus. It also is comprised of 720 Stream Processors, 36 Texture Address Units, and 16 ROPs.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6750 1GB		86 Watts
Radeon HD 3870 1GB		106 Watts
	Difference: 20 Watts (23%)

Memory Bandwidth

In theory, the Radeon HD 3870 1GB is 13% quicker than the Radeon HD 6750 1GB overall, because of its higher data rate. (explain)

Radeon HD 3870 1GB		72000 MB/sec
Radeon HD 6750 1GB		64000 MB/sec
	Difference: 8000 (13%)

Texel Rate

The Radeon HD 6750 1GB will be much (more or less 110%) more effective at texture filtering than the Radeon HD 3870 1GB. (explain)

Radeon HD 6750 1GB		26100 Mtexels/sec
Radeon HD 3870 1GB		12400 Mtexels/sec
	Difference: 13700 (110%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 3870 1GB is superior to the Radeon HD 6750 1GB, though only just barely. (explain)

Radeon HD 3870 1GB		12400 Mpixels/sec
Radeon HD 6750 1GB		11600 Mpixels/sec
	Difference: 800 (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.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the max amount of information (counted in megabytes per second) that can be transported past the external memory interface in a second. It's worked out by multiplying the interface width by its memory clock speed. If it uses DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster 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 in one second. This is worked out by multiplying the total amount 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 handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly write to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the clock speed of the card. 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 fill rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.