Radeon HD 3870 512MB vs Radeon HD 6850

Intro

Compare those specs to the Radeon HD 6850, which features a GPU core clock speed of 775 MHz, and 1024 MB of GDDR5 RAM running at 1000 MHz through a 256-bit bus. It also features 960 SPUs, 48 TAUs, and 32 ROPs.

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

Theoretically speaking, the Radeon HD 6850 should be quite a bit faster than the Radeon HD 3870 512MB in general. (explain)

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

Texel Rate

The Radeon HD 6850 will be quite a bit (approximately 200%) faster with regards to AF 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 is a lot (more or less 100%) better at anti-aliasing than the Radeon HD 3870 512MB, and also capable of handling higher screen resolutions more effectively. (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 max amount of information (measured in megabytes per second) that can be moved over the external memory interface within a second. It is calculated by multiplying the card's bus width by its memory speed. If the card has DDR memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels the video card could possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.