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

Intro

Compare those specifications to the Radeon HD 3870 512MB, which makes use of a 55 nm design. AMD has set the core speed at 775 MHz. The GDDR3 RAM is set to run at a speed of 900 MHz on this specific card. It features 320(64x5) SPUs along with 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

As far as performance goes, the GeForce 8800 GTS (G80) 640MB should theoretically be a small bit superior to the Radeon HD 3870 512MB in general. (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 much (about 99%) better at AF 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

The Radeon HD 3870 512MB is a lot (more or less 21%) better at full screen anti-aliasing than the GeForce 8800 GTS (G80) 640MB, and should be able to handle higher screen resolutions without losing too much performance. (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 largest amount of information (measured in MB per second) that can be transferred past the external memory interface in a second. The number is calculated by multiplying the bus width by its memory clock speed. In the case of DDR type RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the better 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 number of texture map elements (texels) that are applied in one second. This number is worked out by multiplying the total texture units of the card by the core speed of the chip. The better the texel rate, the better the 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 maximum number of pixels the video card could possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines 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 many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.