Radeon HD 3870 X2 1GB vs Radeon HD 7850

Intro

Compare that to the Radeon HD 7850, which features clock speeds of 860 MHz on the GPU, and 1200 MHz on the 2048 MB of GDDR5 RAM. It features 1024 SPUs along with 64 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 7850 should theoretically perform a small bit faster 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 will be much (more or less 108%) faster with regards to 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

The Radeon HD 7850 will be a little bit (about 4%) faster with regards to FSAA than the Radeon HD 3870 X2 1GB, and capable of handling higher resolutions while still performing well. (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 (counted in megabytes per second) that can be transferred across the external memory interface within a second. It is calculated by multiplying the bus width by the speed of its memory. In the case of DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, 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 amount of texture map elements (texels) that are applied in one second. This is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card 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 Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.