Radeon R9 390X 8G vs Radeon R9 M385X

Intro

Compare those specifications to the Radeon R9 M385X, which has a clock speed of 1100 MHz and a GDDR5 memory frequency of 1500 MHz. It also uses a 128-bit bus, and makes use of a 28 nm design. It is made up of 896 SPUs, 56 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon R9 390X 8G should perform quite a bit faster than the Radeon R9 M385X in general. (explain)

Radeon R9 390X 8G		384000 MB/sec
Radeon R9 M385X		96000 MB/sec
	Difference: 288000 (300%)

Texel Rate

The Radeon R9 390X 8G is quite a bit (approximately 200%) better at AF than the Radeon R9 M385X. (explain)

Radeon R9 390X 8G		184800 Mtexels/sec
Radeon R9 M385X		61600 Mtexels/sec
	Difference: 123200 (200%)

Pixel Rate

The Radeon R9 390X 8G should be quite a bit (about 282%) better at anti-aliasing than the Radeon R9 M385X, and also will be capable of handling higher resolutions more effectively. (explain)

Radeon R9 390X 8G		67200 Mpixels/sec
Radeon R9 M385X		17600 Mpixels/sec
	Difference: 49600 (282%)

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.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the max amount of information (in units of megabytes per second) that can be transported past the external memory interface in a second. It is calculated by multiplying the card's bus width by its memory speed. In the case of DDR type memory, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This is calculated by multiplying the total amount of texture units by the core speed of the chip. The higher the texel rate, the better the graphics card will be at 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 write to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of ROPs by the the core 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 fill rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.