GeForce 8800 GTS (G80) 640MB vs Radeon HD 6770

Intro

Compare all that to the Radeon HD 6770, which has a clock speed of 900 MHz and a GDDR5 memory frequency of 1050 MHz. It also uses a 128-bit bus, and makes use of a 40 nm design. It features 800 SPUs, 40 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6770		108 Watts
GeForce 8800 GTS (G80) 640MB		143 Watts
	Difference: 35 Watts (32%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 6770 will be 6% faster than the GeForce 8800 GTS (G80) 640MB in general, because of its greater bandwidth. (explain)

Radeon HD 6770		67200 MB/sec
GeForce 8800 GTS (G80) 640MB		63360 MB/sec
	Difference: 3840 (6%)

Texel Rate

The Radeon HD 6770 should be much (more or less 46%) faster with regards to anisotropic filtering than the GeForce 8800 GTS (G80) 640MB. (explain)

Radeon HD 6770		36000 Mtexels/sec
GeForce 8800 GTS (G80) 640MB		24624 Mtexels/sec
	Difference: 11376 (46%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 6770 is a better choice, by far. (explain)

Radeon HD 6770		14400 Mpixels/sec
GeForce 8800 GTS (G80) 640MB		10260 Mpixels/sec
	Difference: 4140 (40%)

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 (in units of MB per second) that can be transported over the external memory interface in one second. It is worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better 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 number of texture map elements (texels) that can be processed in one second. This number is worked out by multiplying the total amount of texture units by the core speed of the chip. The better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip 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 amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.