Radeon HD 3870 X2 512MB vs Radeon R9 390 8G

Intro

Compare those specs to the Radeon R9 390 8G, which uses a 28 nm design. AMD has set the core frequency at 1000 MHz. The GDDR5 RAM works at a speed of 1500 MHz on this particular card. It features 2560 SPUs along with 160 TAUs and 64 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

As far as performance goes, the Radeon R9 390 8G should theoretically be a lot better than the Radeon HD 3870 X2 512MB overall. (explain)

Radeon R9 390 8G		384000 MB/sec
Radeon HD 3870 X2 512MB		115200 MB/sec
	Difference: 268800 (233%)

Texel Rate

The Radeon R9 390 8G will be much (approximately 506%) better at AF than the Radeon HD 3870 X2 512MB. (explain)

Radeon R9 390 8G		160000 Mtexels/sec
Radeon HD 3870 X2 512MB		26400 Mtexels/sec
	Difference: 133600 (506%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon R9 390 8G is the winner, by a large margin. (explain)

Radeon R9 390 8G		64000 Mpixels/sec
Radeon HD 3870 X2 512MB		26400 Mpixels/sec
	Difference: 37600 (142%)

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 maximum amount of data (counted in megabytes per second) that can be transferred over the external memory interface in one second. The number is calculated by multiplying the card's bus width by its memory speed. If it uses DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed in one second. This is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly record to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to 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 ability to reach the max fill rate.