Radeon HD 3870 X2 512MB vs Radeon R9 M385X

Intro

Compare all that to the Radeon R9 M385X, which comes with GPU clock speed of 1100 MHz, and 4096 MB of GDDR5 memory running at 1500 MHz through a 128-bit bus. It also is made up of 896 Stream Processors, 56 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Performance-wise, the Radeon HD 3870 X2 512MB should theoretically be just a bit better than the Radeon R9 M385X overall. (explain)

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

Texel Rate

The Radeon R9 M385X will be much (about 133%) more effective 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

The Radeon HD 3870 X2 512MB will be much (about 50%) better at anti-aliasing than the Radeon R9 M385X, and able to handle higher screen resolutions without losing too much performance. (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: Memory bandwidth is the max amount of information (in units of megabytes per second) that can be transferred past the external memory interface in one second. The number is calculated by multiplying the card's bus width by the speed of its memory. If the card has DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This number is worked out by multiplying the total 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 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 graphics card can possibly record to its local memory per second - measured in millions of pixels per second. The figure 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 filling the screen with pixels (the image). The actual pixel rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.