Radeon HD 3870 X2 512MB vs Radeon R9 M385X

Intro

Compare that to the Radeon R9 M385X, which uses a 28 nm design. AMD has set the core frequency at 1100 MHz. The GDDR5 memory is set to run at a frequency of 1500 MHz on this card. It features 896 SPUs as well as 56 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 3870 X2 512MB will be 20% quicker than the Radeon R9 M385X in general, due to its higher data rate. (explain)

Radeon HD 3870 X2 512MB		115200 MB/sec
Radeon R9 M385X		96000 MB/sec
	Difference: 19200 (20%)

Texel Rate

The Radeon R9 M385X should be quite a bit (approximately 133%) better at texture filtering than the Radeon HD 3870 X2 512MB. (explain)

Radeon R9 M385X		61600 Mtexels/sec
Radeon HD 3870 X2 512MB		26400 Mtexels/sec
	Difference: 35200 (133%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 3870 X2 512MB is a better choice, and very much so. (explain)

Radeon HD 3870 X2 512MB		26400 Mpixels/sec
Radeon R9 M385X		17600 Mpixels/sec
	Difference: 8800 (50%)

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 data (measured in MB per second) that can be transferred past the external memory interface in a second. It's worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR RAM, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly record to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.