GeForce GTX 580 vs Radeon HD 4890 2GB

Intro

Compare those specs to the Radeon HD 4890 2GB, which has 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 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

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

Memory Bandwidth

The GeForce GTX 580, in theory, should perform a lot faster than the Radeon HD 4890 2GB overall. (explain)

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

Texel Rate

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

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

Pixel Rate

The GeForce GTX 580 is a lot (about 132%) better at full screen anti-aliasing than the Radeon HD 4890 2GB, and also will be capable of handling higher resolutions better. (explain)

GeForce GTX 580		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 data (in units of MB per second) that can be transported across the external memory interface in a second. The number is calculated by multiplying the card's bus width by the speed of its memory. If it uses DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This is calculated by multiplying the total texture units by the core speed of the chip. The better the texel rate, the better the 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 amount of pixels the video card can possibly write to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.