GeForce 8800 GTS (G80) 320MB vs Radeon HD 3870 1GB

Intro

Compare all that to the Radeon HD 3870 1GB, which makes use of a 55 nm design. AMD has set the core frequency at 775 MHz. The GDDR4 RAM works at a frequency of 1125 MHz on this specific model. It features 320(64x5) SPUs as well as 16 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 1GB		106 Watts
GeForce 8800 GTS (G80) 320MB		143 Watts
	Difference: 37 Watts (35%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 3870 1GB is 14% quicker than the GeForce 8800 GTS (G80) 320MB overall, due to its greater data rate. (explain)

Radeon HD 3870 1GB		72000 MB/sec
GeForce 8800 GTS (G80) 320MB		63360 MB/sec
	Difference: 8640 (14%)

Texel Rate

The GeForce 8800 GTS (G80) 320MB should be quite a bit (approximately 99%) better at anisotropic filtering than the Radeon HD 3870 1GB. (explain)

GeForce 8800 GTS (G80) 320MB		24624 Mtexels/sec
Radeon HD 3870 1GB		12400 Mtexels/sec
	Difference: 12224 (99%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 3870 1GB is the winner, and very much so. (explain)

Radeon HD 3870 1GB		12400 Mpixels/sec
GeForce 8800 GTS (G80) 320MB		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 MB per second) that can be transported past the external memory interface within a second. It is worked out by multiplying the card's interface width by its memory clock speed. If the card has DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are 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 this number, the better the card will be at 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 that the graphics chip can possibly write to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.