GeForce GTX 580 3GB vs Radeon HD 4890 1GB

Intro

Compare all that to the Radeon HD 4890 1GB, which comes with a GPU core clock speed of 1000 MHz, and 1024 MB of GDDR5 RAM running at 975 MHz through a 256-bit bus. It also is comprised of 800(160x5) SPUs, 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 1GB		190 Watts
GeForce GTX 580 3GB		244 Watts
	Difference: 54 Watts (28%)

Memory Bandwidth

In theory, the GeForce GTX 580 3GB is 54% faster than the Radeon HD 4890 1GB overall, due to its higher bandwidth. (explain)

GeForce GTX 580 3GB		192384 MB/sec
Radeon HD 4890 1GB		124800 MB/sec
	Difference: 67584 (54%)

Texel Rate

The GeForce GTX 580 3GB will be much (approximately 24%) faster with regards to anisotropic filtering than the Radeon HD 4890 1GB. (explain)

GeForce GTX 580 3GB		49408 Mtexels/sec
Radeon HD 4890 1GB		40000 Mtexels/sec
	Difference: 9408 (24%)

Pixel Rate

If using lots of anti-aliasing 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 4890 1GB		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 max amount of data (in units of MB per second) that can be transferred over the external memory interface within a second. The number is calculated by multiplying the card's interface width by its memory speed. If it uses DDR type memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, 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 number of texture map elements (texels) that are processed in one second. This number is calculated by multiplying the total number of texture units 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 applied in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.