GeForce 8800 GTS (G80) 640MB vs Radeon HD 3870 1GB

Intro

Compare all of that to the Radeon HD 3870 1GB, which comes with a GPU core clock speed of 775 MHz, and 1024 MB of GDDR4 memory running at 1125 MHz through a 256-bit bus. It also is comprised of 320(64x5) SPUs, 16 Texture Address Units, and 16 Raster Operation Units.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 1GB		106 Watts
GeForce 8800 GTS (G80) 640MB		143 Watts
	Difference: 37 Watts (35%)

Memory Bandwidth

In theory, the Radeon HD 3870 1GB is 14% faster than the GeForce 8800 GTS (G80) 640MB in general, due to its higher bandwidth. (explain)

Radeon HD 3870 1GB		72000 MB/sec
GeForce 8800 GTS (G80) 640MB		63360 MB/sec
	Difference: 8640 (14%)

Texel Rate

The GeForce 8800 GTS (G80) 640MB is quite a bit (more or less 99%) better at anisotropic filtering than the Radeon HD 3870 1GB. (explain)

GeForce 8800 GTS (G80) 640MB		24624 Mtexels/sec
Radeon HD 3870 1GB		12400 Mtexels/sec
	Difference: 12224 (99%)

Pixel Rate

The Radeon HD 3870 1GB is much (more or less 21%) faster with regards to AA than the GeForce 8800 GTS (G80) 640MB, and also will be capable of handling higher resolutions better. (explain)

Radeon HD 3870 1GB		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 maximum amount of information (measured in megabytes per second) that can be transported past the external memory interface within a second. It's worked out by multiplying the card's bus width by its memory speed. In the case of DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, 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 clock speed of the chip. The better the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly record to its local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.