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

Intro

Compare all that to the Radeon HD 3870 512MB, which features a clock speed of 775 MHz and a GDDR3 memory frequency of 900 MHz. It also features a 256-bit bus, and uses a 55 nm design. It is comprised of 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

Performance-wise, the GeForce 8800 GTS (G80) 640MB should in theory be just a 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 is quite a bit (approximately 99%) more effective at texture 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

The Radeon HD 3870 512MB should be much (approximately 21%) faster with regards to full screen anti-aliasing than the GeForce 8800 GTS (G80) 640MB, and will be capable of handling higher 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 data (counted in megabytes per second) that can be transported over the external memory interface within a second. It's calculated by multiplying the card's interface width by the speed of its memory. In the case of DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.