Radeon HD 3870 X2 1GB vs Radeon HD 7850

Intro

Compare all of that to the Radeon HD 7850, which features a GPU core clock speed of 860 MHz, and 2048 MB of GDDR5 memory running at 1200 MHz through a 256-bit bus. It also is comprised of 1024 Stream Processors, 64 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

As far as performance goes, the Radeon HD 7850 should in theory be just a bit better than the Radeon HD 3870 X2 1GB overall. (explain)

Radeon HD 7850		153600 MB/sec
Radeon HD 3870 X2 1GB		144128 MB/sec
	Difference: 9472 (7%)

Texel Rate

The Radeon HD 7850 should be much (more or less 108%) more effective at AF than the Radeon HD 3870 X2 1GB. (explain)

Radeon HD 7850		55040 Mtexels/sec
Radeon HD 3870 X2 1GB		26400 Mtexels/sec
	Difference: 28640 (108%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 7850 is superior to the Radeon HD 3870 X2 1GB, not by a very large margin though. (explain)

Radeon HD 7850		27520 Mpixels/sec
Radeon HD 3870 X2 1GB		26400 Mpixels/sec
	Difference: 1120 (4%)

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 data (measured in megabytes per second) that can be moved over the external memory interface within a second. The number is calculated by multiplying the bus width by its memory speed. In the case of DDR memory, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.