GeForce 8800 GTS (G80) 640MB vs Radeon HD 6850

Intro

Compare those specifications to the Radeon HD 6850, which features a core clock speed of 775 MHz and a GDDR5 memory frequency of 1000 MHz. It also makes use of a 256-bit memory bus, and makes use of a 40 nm design. It is made up of 960 SPUs, 48 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6850		127 Watts
GeForce 8800 GTS (G80) 640MB		143 Watts
	Difference: 16 Watts (13%)

Memory Bandwidth

Performance-wise, the Radeon HD 6850 should in theory be quite a bit better than the GeForce 8800 GTS (G80) 640MB overall. (explain)

Radeon HD 6850		128000 MB/sec
GeForce 8800 GTS (G80) 640MB		63360 MB/sec
	Difference: 64640 (102%)

Texel Rate

The Radeon HD 6850 should be a lot (more or less 51%) better at AF than the GeForce 8800 GTS (G80) 640MB. (explain)

Radeon HD 6850		37200 Mtexels/sec
GeForce 8800 GTS (G80) 640MB		24624 Mtexels/sec
	Difference: 12576 (51%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 6850 is a better choice, and very much so. (explain)

Radeon HD 6850		24800 Mpixels/sec
GeForce 8800 GTS (G80) 640MB		10260 Mpixels/sec
	Difference: 14540 (142%)

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 maximum amount of data (counted in MB per second) that can be moved past the external memory interface in one second. It's calculated by multiplying the card's bus width by its memory speed. If it uses DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's 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 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 speed of the chip. The better the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output 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 reach the maximum fill rate.