Geforce GTX 680 vs Radeon HD 4850 X2 1GB

Intro

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

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Geforce GTX 680		195 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 55 Watts (28%)

Memory Bandwidth

The Geforce GTX 680 should in theory be quite a bit faster than the Radeon HD 4850 X2 1GB in general. (explain)

Geforce GTX 680		192256 MB/sec
Radeon HD 4850 X2 1GB		127104 MB/sec
	Difference: 65152 (51%)

Texel Rate

The Geforce GTX 680 will be much (more or less 158%) more effective at anisotropic filtering than the Radeon HD 4850 X2 1GB. (explain)

Geforce GTX 680		128768 Mtexels/sec
Radeon HD 4850 X2 1GB		50000 Mtexels/sec
	Difference: 78768 (158%)

Pixel Rate

If running with high levels of AA is important to you, then the Geforce GTX 680 is superior to the Radeon HD 4850 X2 1GB, and very much so. (explain)

Geforce GTX 680		32192 Mpixels/sec
Radeon HD 4850 X2 1GB		20000 Mpixels/sec
	Difference: 12192 (61%)

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 (measured in megabytes per second) that can be transported over the external memory interface in one second. The number is worked out by multiplying the card's bus width by the speed of its memory. If the card has DDR memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly record to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs by the the card's clock speed. 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 rate also depends on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.