Radeon HD 3870 512MB vs Radeon HD 6750 1GB

Intro

Compare that to the Radeon HD 6750 1GB, which comes with GPU core speed of 725 MHz, and 1024 MB of GDDR5 RAM running at 1000 MHz through a 128-bit bus. It also is made up of 720 Stream Processors, 36 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6750 1GB		86 Watts
Radeon HD 3870 512MB		106 Watts
	Difference: 20 Watts (23%)

Memory Bandwidth

The Radeon HD 6750 1GB should theoretically perform a little bit faster than the Radeon HD 3870 512MB overall. (explain)

Radeon HD 6750 1GB		64000 MB/sec
Radeon HD 3870 512MB		57600 MB/sec
	Difference: 6400 (11%)

Texel Rate

The Radeon HD 6750 1GB is quite a bit (approximately 110%) faster with regards to AF than the Radeon HD 3870 512MB. (explain)

Radeon HD 6750 1GB		26100 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 13700 (110%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 3870 512MB is the winner, but it probably won't make a huge difference. (explain)

Radeon HD 3870 512MB		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: Bandwidth is the max amount of data (in units of MB per second) that can be moved past the external memory interface in one second. The number is calculated by multiplying the card's bus width by its memory clock speed. If it uses DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This figure is calculated by multiplying the total texture units by the core speed of the chip. The higher this number, the better the 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 can possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the clock 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 bandwidth is, the lower the ability to reach the max fill rate.