Radeon R9 390 8G vs Radeon R9 M390X

Intro

Compare those specs to the Radeon R9 M390X, which comes with clock speeds of 723 MHz on the GPU, and 1250 MHz on the 4096 MB of GDDR5 memory. It features 2048 SPUs as well as 128 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

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

Memory Bandwidth

As far as performance goes, the Radeon R9 390 8G should theoretically be quite a bit better than the Radeon R9 M390X overall. (explain)

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

Texel Rate

The Radeon R9 390 8G will be much (approximately 73%) faster with regards to AF than the Radeon R9 M390X. (explain)

Radeon R9 390 8G		160000 Mtexels/sec
Radeon R9 M390X		92544 Mtexels/sec
	Difference: 67456 (73%)

Pixel Rate

The Radeon R9 390 8G will be a lot (approximately 177%) faster with regards to FSAA than the Radeon R9 M390X, and should be able to handle higher screen resolutions more effectively. (explain)

Radeon R9 390 8G		64000 Mpixels/sec
Radeon R9 M390X		23136 Mpixels/sec
	Difference: 40864 (177%)

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 data (in units of MB per second) that can be transferred over the external memory interface within a second. The number is worked out by multiplying the card's interface width by its memory clock speed. In the case of DDR type memory, 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, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly record to its 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 card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.