GeForce 8800 GTS (G80) 640MB vs Radeon HD 3850 X2

Intro

Compare those specifications to the Radeon HD 3850 X2, which comes with a GPU core clock speed of 668 MHz, and 512 MB of GDDR3 memory set to run at 828 MHz through a 256-bit bus. It also is comprised of 320(64x5) Stream Processors, 16 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically speaking, the Radeon HD 3850 X2 should perform quite a bit faster than the GeForce 8800 GTS (G80) 640MB in general. (explain)

Radeon HD 3850 X2		105984 MB/sec
GeForce 8800 GTS (G80) 640MB		63360 MB/sec
	Difference: 42624 (67%)

Texel Rate

The GeForce 8800 GTS (G80) 640MB should be just a bit (more or less 15%) more effective at anisotropic filtering than the Radeon HD 3850 X2. (explain)

GeForce 8800 GTS (G80) 640MB		24624 Mtexels/sec
Radeon HD 3850 X2		21376 Mtexels/sec
	Difference: 3248 (15%)

Pixel Rate

The Radeon HD 3850 X2 is a lot (about 108%) better at AA than the GeForce 8800 GTS (G80) 640MB, and will be capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 3850 X2		21376 Mpixels/sec
GeForce 8800 GTS (G80) 640MB		10260 Mpixels/sec
	Difference: 11116 (108%)

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: Memory bandwidth is the max amount of information (counted in megabytes per second) that can be moved across the external memory interface within a second. It's calculated by multiplying the interface width by its memory speed. If it uses DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate 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 filling the screen with pixels (the image). The actual pixel rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.