Radeon HD 3870 X2 1GB vs Radeon HD 5850

Intro

Compare all that to the Radeon HD 5850, which features core speeds of 725 MHz on the GPU, and 1000 MHz on the 1024 MB of GDDR5 memory. It features 1440(288x5) SPUs as well as 72 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically, the Radeon HD 3870 X2 1GB should perform a bit faster than the Radeon HD 5850 overall. (explain)

Radeon HD 3870 X2 1GB		144128 MB/sec
Radeon HD 5850		128000 MB/sec
	Difference: 16128 (13%)

Texel Rate

The Radeon HD 5850 should be a lot (more or less 98%) better at texture filtering than the Radeon HD 3870 X2 1GB. (explain)

Radeon HD 5850		52200 Mtexels/sec
Radeon HD 3870 X2 1GB		26400 Mtexels/sec
	Difference: 25800 (98%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 3870 X2 1GB is a better choice, though only just barely. (explain)

Radeon HD 3870 X2 1GB		26400 Mpixels/sec
Radeon HD 5850		23200 Mpixels/sec
	Difference: 3200 (14%)

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 data (counted in megabytes per second) that can be moved past the external memory interface within a second. It is calculated by multiplying the bus width by its memory clock speed. In the case of DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, 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 texture map elements (texels) that are processed per second. This number is calculated by multiplying the total texture units of the card by the core speed of the chip. The better the texel rate, the better the video 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 that the graphics chip could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of ROPs by the the core clock speed. 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 is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.