GeForce 8800 GTS (G80) 640MB vs Radeon HD 4850 X2 512MB

Intro

Compare those specifications to the Radeon HD 4850 X2 512MB, which uses a 55 nm design. ATi has set the core speed at 625 MHz. The GDDR3 RAM works at a speed of 993 MHz on this particular card. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 Rasterization Operator Units.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 8800 GTS (G80) 640MB		143 Watts
Radeon HD 4850 X2 512MB		250 Watts
	Difference: 107 Watts (75%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4850 X2 512MB should theoretically be much better than the GeForce 8800 GTS (G80) 640MB in general. (explain)

Radeon HD 4850 X2 512MB		127104 MB/sec
GeForce 8800 GTS (G80) 640MB		63360 MB/sec
	Difference: 63744 (101%)

Texel Rate

The Radeon HD 4850 X2 512MB should be a lot (approximately 103%) faster with regards to AF than the GeForce 8800 GTS (G80) 640MB. (explain)

Radeon HD 4850 X2 512MB		50000 Mtexels/sec
GeForce 8800 GTS (G80) 640MB		24624 Mtexels/sec
	Difference: 25376 (103%)

Pixel Rate

The Radeon HD 4850 X2 512MB will be much (more or less 95%) better at full screen anti-aliasing than the GeForce 8800 GTS (G80) 640MB, and will be capable of handling higher screen resolutions without slowing down too much. (explain)

Radeon HD 4850 X2 512MB		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 megabytes per second) that can be transported over the external memory interface within a second. It is worked out by multiplying the card's bus width by the speed of its memory. In the case of DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the better 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 amount of texture units of the card by the core speed of the chip. The higher the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly record to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.