GeForce GTX 280 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 RAM. 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 280		236 Watts
	Difference: 46 Watts (24%)

Memory Bandwidth

As far as performance goes, the GeForce GTX 280 should theoretically be just a bit better than the Radeon HD 4890 2GB overall. (explain)

GeForce GTX 280		141696 MB/sec
Radeon HD 4890 2GB		124800 MB/sec
	Difference: 16896 (14%)

Texel Rate

The GeForce GTX 280 is a little bit (about 20%) more effective at texture filtering than the Radeon HD 4890 2GB. (explain)

GeForce GTX 280		48160 Mtexels/sec
Radeon HD 4890 2GB		40000 Mtexels/sec
	Difference: 8160 (20%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the GeForce GTX 280 is the winner, but not by far. (explain)

GeForce GTX 280		19264 Mpixels/sec
Radeon HD 4890 2GB		16000 Mpixels/sec
	Difference: 3264 (20%)

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 largest amount of data (in units of megabytes per second) that can be transferred past the external memory interface in a second. It is calculated by multiplying the interface width by its memory speed. If the card has DDR RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied per second. This number is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The better this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly record to its local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units 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 fill rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.