Radeon HD 3870 1GB vs Radeon HD 3870 X2 512MB

Intro

Compare those specifications to the Radeon HD 3870 X2 512MB, which features a GPU core clock speed of 825 MHz, and 512 MB of GDDR3 RAM set to run at 900 MHz through a 256-bit bus. It also is made up of 320(64x5) Stream Processors, 16 Texture Address Units, and 16 Raster Operation Units.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 3870 X2 512MB, in theory, should perform quite a bit faster than the Radeon HD 3870 1GB overall. (explain)

Radeon HD 3870 X2 512MB		115200 MB/sec
Radeon HD 3870 1GB		72000 MB/sec
	Difference: 43200 (60%)

Texel Rate

The Radeon HD 3870 X2 512MB will be much (approximately 113%) faster with regards to texture filtering than the Radeon HD 3870 1GB. (explain)

Radeon HD 3870 X2 512MB		26400 Mtexels/sec
Radeon HD 3870 1GB		12400 Mtexels/sec
	Difference: 14000 (113%)

Pixel Rate

The Radeon HD 3870 X2 512MB is much (about 113%) faster with regards to full screen anti-aliasing than the Radeon HD 3870 1GB, and also should be capable of handling higher screen resolutions without slowing down too much. (explain)

Radeon HD 3870 X2 512MB		26400 Mpixels/sec
Radeon HD 3870 1GB		12400 Mpixels/sec
	Difference: 14000 (113%)

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: Bandwidth is the max amount of information (measured in megabytes per second) that can be moved past the external memory interface within a second. It's calculated by multiplying the card's bus width by its memory speed. If it uses DDR type RAM, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed in one second. This number is calculated by multiplying the total number of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the video card will be at handling 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 card can possibly record to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the amount 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 output rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.