GeForce 8800 GTS (G80) 320MB vs Radeon HD 3870 X2 512MB

Intro

Compare that to the Radeon HD 3870 X2 512MB, which makes use of a 55 nm design. AMD has set the core frequency at 825 MHz. The GDDR3 RAM works at a speed of 900 MHz on this 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

Memory Bandwidth

Performance-wise, the Radeon HD 3870 X2 512MB should in theory be a lot better than the GeForce 8800 GTS (G80) 320MB overall. (explain)

Radeon HD 3870 X2 512MB		115200 MB/sec
GeForce 8800 GTS (G80) 320MB		63360 MB/sec
	Difference: 51840 (82%)

Texel Rate

The Radeon HD 3870 X2 512MB should be just a bit (more or less 7%) better at texture filtering than the GeForce 8800 GTS (G80) 320MB. (explain)

Radeon HD 3870 X2 512MB		26400 Mtexels/sec
GeForce 8800 GTS (G80) 320MB		24624 Mtexels/sec
	Difference: 1776 (7%)

Pixel Rate

The Radeon HD 3870 X2 512MB should be a lot (more or less 157%) better at AA than the GeForce 8800 GTS (G80) 320MB, and also should be capable of handling higher resolutions without slowing down too much. (explain)

Radeon HD 3870 X2 512MB		26400 Mpixels/sec
GeForce 8800 GTS (G80) 320MB		10260 Mpixels/sec
	Difference: 16140 (157%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the maximum amount of information (in units of megabytes per second) that can be transported past the external memory interface in a second. It is worked out by multiplying the interface width by the speed of its memory. If the card has DDR type memory, the result should 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, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.