Radeon HD 3870 X2 512MB vs Radeon HD 6850

Intro

Compare those specs to the Radeon HD 6850, which makes use of a 40 nm design. AMD has clocked the core frequency at 775 MHz. The GDDR5 memory works at a frequency of 1000 MHz on this particular card. It features 960 SPUs as well as 48 Texture Address Units and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically speaking, the Radeon HD 6850 should be a small bit faster than the Radeon HD 3870 X2 512MB overall. (explain)

Radeon HD 6850		128000 MB/sec
Radeon HD 3870 X2 512MB		115200 MB/sec
	Difference: 12800 (11%)

Texel Rate

The Radeon HD 6850 will be a lot (about 41%) better at texture filtering than the Radeon HD 3870 X2 512MB. (explain)

Radeon HD 6850		37200 Mtexels/sec
Radeon HD 3870 X2 512MB		26400 Mtexels/sec
	Difference: 10800 (41%)

Pixel Rate

The Radeon HD 3870 X2 512MB should be just a bit (about 6%) more effective at FSAA than the Radeon HD 6850, and able to handle higher resolutions more effectively. (explain)

Radeon HD 3870 X2 512MB		26400 Mpixels/sec
Radeon HD 6850		24800 Mpixels/sec
	Difference: 1600 (6%)

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: Bandwidth is the largest amount of data (in units of MB per second) that can be transported across the external memory interface in a second. The number is calculated by multiplying the card's interface width by its memory clock speed. If the card has DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly write to its local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.