GeForce GTX 580 3GB vs Radeon HD 4850 X2 512MB

Intro

Compare those specifications to the Radeon HD 4850 X2 512MB, which has a clock speed of 625 MHz and a GDDR3 memory speed of 993 MHz. It also features 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 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 580 3GB		244 Watts
Radeon HD 4850 X2 512MB		250 Watts
	Difference: 6 Watts (2%)

Memory Bandwidth

In theory, the GeForce GTX 580 3GB should be 51% quicker than the Radeon HD 4850 X2 512MB in general, because of its higher data rate. (explain)

GeForce GTX 580 3GB		192384 MB/sec
Radeon HD 4850 X2 512MB		127104 MB/sec
	Difference: 65280 (51%)

Texel Rate

The Radeon HD 4850 X2 512MB is a little bit (about 1%) better at AF than the GeForce GTX 580 3GB. (explain)

Radeon HD 4850 X2 512MB		50000 Mtexels/sec
GeForce GTX 580 3GB		49408 Mtexels/sec
	Difference: 592 (1%)

Pixel Rate

If running with a high screen resolution is important to you, then the GeForce GTX 580 3GB is a better choice, and very much so. (explain)

GeForce GTX 580 3GB		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: Memory bandwidth is the maximum amount of data (counted in MB per second) that can be transferred past the external memory interface in a second. It is worked out by multiplying the interface width by its memory clock speed. If it uses DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, 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 processed per second. This number is worked out by multiplying the total texture units by the core speed of the chip. The higher the texel rate, the better the video card will be at 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 the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.