Geforce GTX 680 vs Radeon HD 4850 X2 1GB

Intro

Compare those specs to the Radeon HD 4850 X2 1GB, which makes use of a 55 nm design. AMD has clocked the core speed at 625 MHz. The GDDR3 RAM is set to run at a frequency of 993 MHz on this model. It features 800(160x5) SPUs as well as 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

In theory, the Geforce GTX 680 should be quite a bit faster than the Radeon HD 4850 X2 1GB overall. (explain)

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

Texel Rate

The Geforce GTX 680 should be a lot (approximately 158%) faster with regards to AF 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

The Geforce GTX 680 will be a lot (approximately 61%) better at anti-aliasing than the Radeon HD 4850 X2 1GB, and also will be capable of handling higher screen resolutions without slowing down too much. (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 data (in units of MB per second) that can be transferred over the external memory interface in a second. It's worked out by multiplying the card's bus width by its memory speed. In the case of DDR memory, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.