GeForce GTS 250 512MB vs Radeon HD 4850 X2 1GB

Intro

Compare all of that to the Radeon HD 4850 X2 1GB, which features a clock speed of 625 MHz and a GDDR3 memory speed of 993 MHz. It also uses a 256-bit memory bus, and uses a 55 nm design. It is made up of 800(160x5) SPUs, 40 Texture Address Units, and 16 Raster Operation Units.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTS 250 512MB		145 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 105 Watts (72%)

Memory Bandwidth

In theory, the Radeon HD 4850 X2 1GB will be 81% quicker than the GeForce GTS 250 512MB overall, because of its greater bandwidth. (explain)

Radeon HD 4850 X2 1GB		127104 MB/sec
GeForce GTS 250 512MB		70400 MB/sec
	Difference: 56704 (81%)

Texel Rate

The Radeon HD 4850 X2 1GB is just a bit (about 6%) better at anisotropic filtering than the GeForce GTS 250 512MB. (explain)

Radeon HD 4850 X2 1GB		50000 Mtexels/sec
GeForce GTS 250 512MB		47232 Mtexels/sec
	Difference: 2768 (6%)

Pixel Rate

The Radeon HD 4850 X2 1GB will be much (approximately 69%) more effective at FSAA than the GeForce GTS 250 512MB, and also will be able to handle higher screen resolutions more effectively. (explain)

Radeon HD 4850 X2 1GB		20000 Mpixels/sec
GeForce GTS 250 512MB		11808 Mpixels/sec
	Difference: 8192 (69%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the max amount of information (measured in megabytes per second) that can be transported over the external memory interface in one second. It is calculated by multiplying the bus width by its memory speed. In the case of DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly record to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.