Radeon HD 3870 X2 1GB vs Radeon HD 7950 3GB

Intro

Compare those specifications to the Radeon HD 7950 3GB, which has a clock frequency of 800 MHz and a GDDR5 memory frequency of 1250 MHz. It also makes use of a 384-bit bus, and uses a 28 nm design. It features 1792 SPUs, 112 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 7950 3GB should be 67% quicker than the Radeon HD 3870 X2 1GB overall, because of its higher data rate. (explain)

Radeon HD 7950 3GB		240000 MB/sec
Radeon HD 3870 X2 1GB		144128 MB/sec
	Difference: 95872 (67%)

Texel Rate

The Radeon HD 7950 3GB is a lot (more or less 239%) better at AF than the Radeon HD 3870 X2 1GB. (explain)

Radeon HD 7950 3GB		89600 Mtexels/sec
Radeon HD 3870 X2 1GB		26400 Mtexels/sec
	Difference: 63200 (239%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 3870 X2 1GB is a better choice, though not by far. (explain)

Radeon HD 3870 X2 1GB		26400 Mpixels/sec
Radeon HD 7950 3GB		25600 Mpixels/sec
	Difference: 800 (3%)

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

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.