Radeon R9 390X 8G vs Radeon R9 M390X

Intro

Compare those specs to the Radeon R9 M390X, which features a GPU core clock speed of 723 MHz, and 4096 MB of GDDR5 memory running at 1250 MHz through a 256-bit bus. It also features 2048 SPUs, 128 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R9 M390X		125 Watts
Radeon R9 390X 8G		275 Watts
	Difference: 150 Watts (120%)

Memory Bandwidth

In theory, the Radeon R9 390X 8G should be quite a bit faster than the Radeon R9 M390X in general. (explain)

Radeon R9 390X 8G		384000 MB/sec
Radeon R9 M390X		160000 MB/sec
	Difference: 224000 (140%)

Texel Rate

The Radeon R9 390X 8G will be quite a bit (about 100%) better at texture filtering than the Radeon R9 M390X. (explain)

Radeon R9 390X 8G		184800 Mtexels/sec
Radeon R9 M390X		92544 Mtexels/sec
	Difference: 92256 (100%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon R9 390X 8G is a better choice, by a large margin. (explain)

Radeon R9 390X 8G		67200 Mpixels/sec
Radeon R9 M390X		23136 Mpixels/sec
	Difference: 44064 (190%)

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 largest amount of information (in units of MB per second) that can be moved across the external memory interface within a second. It is calculated by multiplying the bus width by the speed of its memory. In the case of DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed in one second. This is worked out by multiplying the total number of texture units by the core clock 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 in one second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.