Radeon HD 3870 X2 1GB vs Radeon HD 7950

Intro

Compare all that to the Radeon HD 7950, which comes with a core clock speed of 800 MHz and a GDDR5 memory speed of 1250 MHz. It also makes use of a 384-bit bus, and makes use of a 28 nm design. It is comprised of 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 will be 67% faster than the Radeon HD 3870 X2 1GB in general, because of its greater bandwidth. (explain)

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

Texel Rate

The Radeon HD 7950 should be quite a bit (about 239%) faster with regards to anisotropic filtering than the Radeon HD 3870 X2 1GB. (explain)

Radeon HD 7950		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 superior to the Radeon HD 7950, but not by far. (explain)

Radeon HD 3870 X2 1GB		26400 Mpixels/sec
Radeon HD 7950		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 max amount of data (measured in megabytes per second) that can be moved across the external memory interface within a second. The number is calculated by multiplying the bus width by the speed of its memory. If it uses DDR memory, it should be multiplied by 2 once 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 processed per second. This number is calculated by multiplying the total texture units by the core speed of the chip. The better the texel rate, the better the graphics 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 could possibly record to the 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 clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.