GeForce 8800 GTS (G80) 640MB vs Radeon HD 3870 X2 512MB

Intro

Compare all that to the Radeon HD 3870 X2 512MB, which comes with core speeds of 825 MHz on the GPU, and 900 MHz on the 512 MB of GDDR3 RAM. It features 320(64x5) SPUs along with 16 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 3870 X2 512MB will be 82% quicker than the GeForce 8800 GTS (G80) 640MB overall, because of its higher bandwidth. (explain)

Radeon HD 3870 X2 512MB		115200 MB/sec
GeForce 8800 GTS (G80) 640MB		63360 MB/sec
	Difference: 51840 (82%)

Texel Rate

The Radeon HD 3870 X2 512MB will be just a bit (approximately 7%) faster with regards to texture filtering than the GeForce 8800 GTS (G80) 640MB. (explain)

Radeon HD 3870 X2 512MB		26400 Mtexels/sec
GeForce 8800 GTS (G80) 640MB		24624 Mtexels/sec
	Difference: 1776 (7%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 3870 X2 512MB is the winner, and very much so. (explain)

Radeon HD 3870 X2 512MB		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 maximum amount of data (counted in MB per second) that can be transferred across the external memory interface in a second. It's calculated by multiplying the card's interface width by its memory clock speed. If it uses DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range 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 number of texture units by the core speed of the chip. The higher the texel rate, 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 most pixels the graphics card could possibly record to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.