GeForce 8800 GTS (G80) 640MB vs Radeon HD 3870 X2 1GB

Intro

Compare those specs to the Radeon HD 3870 X2 1GB, which makes use of a 55 nm design. AMD has set the core speed at 825 MHz. The GDDR4 memory runs at a frequency of 1126 MHz on this specific card. 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

Theoretically, the Radeon HD 3870 X2 1GB should perform a lot faster than the GeForce 8800 GTS (G80) 640MB overall. (explain)

Radeon HD 3870 X2 1GB		144128 MB/sec
GeForce 8800 GTS (G80) 640MB		63360 MB/sec
	Difference: 80768 (127%)

Texel Rate

The Radeon HD 3870 X2 1GB will be a bit (approximately 7%) better at texture filtering than the GeForce 8800 GTS (G80) 640MB. (explain)

Radeon HD 3870 X2 1GB		26400 Mtexels/sec
GeForce 8800 GTS (G80) 640MB		24624 Mtexels/sec
	Difference: 1776 (7%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 3870 X2 1GB is the winner, and very much so. (explain)

Radeon HD 3870 X2 1GB		26400 Mpixels/sec
GeForce 8800 GTS (G80) 640MB		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 max amount of data (in units of megabytes per second) that can be transferred past the external memory interface in one second. It is calculated by multiplying the interface width by its memory clock speed. In the case of DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the card's 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 can be applied per second. This is worked out by multiplying the total texture units 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 applied in a second.

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