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

Intro

Compare those specifications to the Radeon HD 4850 X2 1GB, which features a core clock speed of 625 MHz and a GDDR3 memory frequency of 993 MHz. It also uses a 256-bit bus, and uses a 55 nm design. It is comprised of 800(160x5) SPUs, 40 TAUs, and 16 Raster Operation Units.

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

Theoretically speaking, the Radeon HD 4850 X2 1GB should be quite a bit faster than 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 quite a bit (more or less 103%) more effective 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

If using a high screen resolution is important to you, then the Radeon HD 4850 X2 1GB is the winner, by a large margin. (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 maximum amount of data (in units of MB per second) that can be transferred across the external memory interface in one second. It is worked out by multiplying the interface width by its memory speed. In the case of DDR RAM, the result should be multiplied by 2 once 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, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed in one second. This number is worked out by multiplying the total texture units of the card by the core clock 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 in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.