GeForce GTX 280 vs Radeon HD 4890 1GB

Intro

Compare those specs to the Radeon HD 4890 1GB, which features a core clock frequency of 1000 MHz and a GDDR5 memory speed of 975 MHz. It also uses a 256-bit memory bus, and makes use of a 55 nm design. It features 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 280		236 Watts
	Difference: 46 Watts (24%)

Memory Bandwidth

In theory, the GeForce GTX 280 should be 14% quicker than the Radeon HD 4890 1GB in general, because of its greater data rate. (explain)

GeForce GTX 280		141696 MB/sec
Radeon HD 4890 1GB		124800 MB/sec
	Difference: 16896 (14%)

Texel Rate

The GeForce GTX 280 will be just a bit (more or less 20%) better at texture filtering than the Radeon HD 4890 1GB. (explain)

GeForce GTX 280		48160 Mtexels/sec
Radeon HD 4890 1GB		40000 Mtexels/sec
	Difference: 8160 (20%)

Pixel Rate

If running with a high screen resolution is important to you, then the GeForce GTX 280 is the winner, not by a very large margin though. (explain)

GeForce GTX 280		19264 Mpixels/sec
Radeon HD 4890 1GB		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 max amount of data (counted in megabytes per second) that can be moved across the external memory interface in one second. It is worked out by multiplying the bus width by its memory speed. In the case of DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.