Radeon HD 3870 512MB vs Radeon HD 6850

Intro

Compare that to the Radeon HD 6850, which makes use of a 40 nm design. AMD has set the core speed at 775 MHz. The GDDR5 RAM is set to run at a speed of 1000 MHz on this specific model. It features 960 SPUs as well as 48 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 512MB		106 Watts
Radeon HD 6850		127 Watts
	Difference: 21 Watts (20%)

Memory Bandwidth

The Radeon HD 6850 should in theory be a lot faster than the Radeon HD 3870 512MB overall. (explain)

Radeon HD 6850		128000 MB/sec
Radeon HD 3870 512MB		57600 MB/sec
	Difference: 70400 (122%)

Texel Rate

The Radeon HD 6850 is much (more or less 200%) better at texture filtering than the Radeon HD 3870 512MB. (explain)

Radeon HD 6850		37200 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 24800 (200%)

Pixel Rate

The Radeon HD 6850 will be quite a bit (more or less 100%) better at anti-aliasing than the Radeon HD 3870 512MB, and also capable of handling higher resolutions better. (explain)

Radeon HD 6850		24800 Mpixels/sec
Radeon HD 3870 512MB		12400 Mpixels/sec
	Difference: 12400 (100%)

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 maximum amount of data (measured in megabytes per second) that can be transferred past the external memory interface within a second. It is worked out by multiplying the card's bus width by its memory speed. In the case of DDR memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the 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 texture map elements (texels) that can be applied in one second. This figure is worked out by multiplying the total texture units by the core clock speed of the chip. The better this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.