GeForce 8800 GTS (G80) 640MB vs Radeon HD 4850 X2 1GB

Intro

Compare that to the Radeon HD 4850 X2 1GB, which has a core clock frequency of 625 MHz and a GDDR3 memory frequency of 993 MHz. It also makes use of a 256-bit bus, and makes use of a 55 nm design. It is made up of 800(160x5) SPUs, 40 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 8800 GTS (G80) 640MB		143 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 107 Watts (75%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4850 X2 1GB should in theory be much superior to the GeForce 8800 GTS (G80) 640MB in general. (explain)

Radeon HD 4850 X2 1GB		127104 MB/sec
GeForce 8800 GTS (G80) 640MB		63360 MB/sec
	Difference: 63744 (101%)

Texel Rate

The Radeon HD 4850 X2 1GB should be much (more or less 103%) better at anisotropic filtering than the GeForce 8800 GTS (G80) 640MB. (explain)

Radeon HD 4850 X2 1GB		50000 Mtexels/sec
GeForce 8800 GTS (G80) 640MB		24624 Mtexels/sec
	Difference: 25376 (103%)

Pixel Rate

The Radeon HD 4850 X2 1GB is much (approximately 95%) more effective at anti-aliasing than the GeForce 8800 GTS (G80) 640MB, and also should be capable of handling higher screen resolutions more effectively. (explain)

Radeon HD 4850 X2 1GB		20000 Mpixels/sec
GeForce 8800 GTS (G80) 640MB		10260 Mpixels/sec
	Difference: 9740 (95%)

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 information (counted in MB per second) that can be transferred over the external memory interface within a second. The number is worked out by multiplying the card's interface width by the speed of its memory. In the case of DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the better 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 amount of texture map elements (texels) that are processed in one second. This number is calculated by multiplying the total texture units by the core speed of the chip. The better this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly record to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.