GeForce GTS 250 512MB vs Radeon HD 3870 X2 512MB

Intro

Compare those specifications to the Radeon HD 3870 X2 512MB, which comes with GPU core speed of 825 MHz, and 512 MB of GDDR3 memory running at 900 MHz through a 256-bit bus. It also is made up of 320(64x5) SPUs, 16 TAUs, and 16 ROPs.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Memory Bandwidth

As far as performance goes, the Radeon HD 3870 X2 512MB should theoretically be much better than the GeForce GTS 250 512MB overall. (explain)

Radeon HD 3870 X2 512MB		115200 MB/sec
GeForce GTS 250 512MB		70400 MB/sec
	Difference: 44800 (64%)

Texel Rate

The GeForce GTS 250 512MB will be much (approximately 79%) better at AF than the Radeon HD 3870 X2 512MB. (explain)

GeForce GTS 250 512MB		47232 Mtexels/sec
Radeon HD 3870 X2 512MB		26400 Mtexels/sec
	Difference: 20832 (79%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 3870 X2 512MB is superior to the GeForce GTS 250 512MB, and very much so. (explain)

Radeon HD 3870 X2 512MB		26400 Mpixels/sec
GeForce GTS 250 512MB		11808 Mpixels/sec
	Difference: 14592 (124%)

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 largest amount of information (counted in MB per second) that can be transported across the external memory interface in a second. It is worked out by multiplying the card's bus width by its memory speed. If it uses DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the faster 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 applied in one second. This is worked out by multiplying the total number of texture units by the core speed of the chip. The higher the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.