GeForce GTX 580 3GB vs Radeon HD 4890 2GB

Intro

Compare that to the Radeon HD 4890 2GB, which features core clock speeds of 1000 MHz on the GPU, and 975 MHz on the 2048 MB of GDDR5 memory. 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)

Radeon HD 4890 2GB		190 Watts
GeForce GTX 580 3GB		244 Watts
	Difference: 54 Watts (28%)

Memory Bandwidth

The GeForce GTX 580 3GB, in theory, should perform much faster than the Radeon HD 4890 2GB in general. (explain)

GeForce GTX 580 3GB		192384 MB/sec
Radeon HD 4890 2GB		124800 MB/sec
	Difference: 67584 (54%)

Texel Rate

The GeForce GTX 580 3GB will be a lot (more or less 24%) more effective at AF than the Radeon HD 4890 2GB. (explain)

GeForce GTX 580 3GB		49408 Mtexels/sec
Radeon HD 4890 2GB		40000 Mtexels/sec
	Difference: 9408 (24%)

Pixel Rate

If running with high levels of AA is important to you, then the GeForce GTX 580 3GB is a better choice, by a large margin. (explain)

GeForce GTX 580 3GB		37056 Mpixels/sec
Radeon HD 4890 2GB		16000 Mpixels/sec
	Difference: 21056 (132%)

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.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the maximum amount of information (in units of MB per second) that can be moved over the external memory interface within a second. The number is calculated by multiplying the bus width by the speed of its memory. If the card has DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This figure is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The better 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 that the graphics chip could possibly record to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.