GeForce 8800 GTS (G80) 640MB vs Radeon HD 3870 512MB

Intro

Compare those specifications to the Radeon HD 3870 512MB, which comes with GPU core speed of 775 MHz, and 512 MB of GDDR3 RAM set to run at 900 MHz through a 256-bit bus. It also features 320(64x5) SPUs, 16 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 512MB		106 Watts
GeForce 8800 GTS (G80) 640MB		143 Watts
	Difference: 37 Watts (35%)

Memory Bandwidth

In theory, the GeForce 8800 GTS (G80) 640MB should be 10% quicker than the Radeon HD 3870 512MB overall, because of its greater bandwidth. (explain)

GeForce 8800 GTS (G80) 640MB		63360 MB/sec
Radeon HD 3870 512MB		57600 MB/sec
	Difference: 5760 (10%)

Texel Rate

The GeForce 8800 GTS (G80) 640MB will be quite a bit (more or less 99%) faster with regards to anisotropic filtering than the Radeon HD 3870 512MB. (explain)

GeForce 8800 GTS (G80) 640MB		24624 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 12224 (99%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 3870 512MB is the winner, by far. (explain)

Radeon HD 3870 512MB		12400 Mpixels/sec
GeForce 8800 GTS (G80) 640MB		10260 Mpixels/sec
	Difference: 2140 (21%)

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 max amount of data (counted in megabytes per second) that can be transported over the external memory interface in a second. It is worked out by multiplying the interface width by its memory speed. In the case of DDR memory, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Raster Operations Pipelines by the clock speed of the card. 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 rate also depends on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.