GeForce GTX 580 vs Radeon HD 4850 X2 512MB

Intro

Compare that to the Radeon HD 4850 X2 512MB, which has core speeds of 625 MHz on the GPU, and 993 MHz on the 512 MB of GDDR3 memory. It features 800(160x5) SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 580		244 Watts
Radeon HD 4850 X2 512MB		250 Watts
	Difference: 6 Watts (2%)

Memory Bandwidth

In theory, the GeForce GTX 580 should be 51% quicker than the Radeon HD 4850 X2 512MB in general, due to its higher bandwidth. (explain)

GeForce GTX 580		192384 MB/sec
Radeon HD 4850 X2 512MB		127104 MB/sec
	Difference: 65280 (51%)

Texel Rate

The Radeon HD 4850 X2 512MB will be a little bit (approximately 1%) more effective at anisotropic filtering than the GeForce GTX 580. (explain)

Radeon HD 4850 X2 512MB		50000 Mtexels/sec
GeForce GTX 580		49408 Mtexels/sec
	Difference: 592 (1%)

Pixel Rate

The GeForce GTX 580 will be a lot (about 85%) more effective at full screen anti-aliasing than the Radeon HD 4850 X2 512MB, and also capable of handling higher screen resolutions while still performing well. (explain)

GeForce GTX 580		37056 Mpixels/sec
Radeon HD 4850 X2 512MB		20000 Mpixels/sec
	Difference: 17056 (85%)

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 (measured in MB per second) that can be transported across the external memory interface in a second. It's calculated by multiplying the card's bus width by its memory clock speed. If it uses DDR memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied per second. This number is calculated by multiplying the total texture units of the card by the core clock 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 in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.