Radeon R5 M255 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 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

As far as performance goes, the Radeon R9 M390X should theoretically be quite a bit better than the Radeon R5 M255 overall. (explain)

Radeon R9 M390X		160000 MB/sec
Radeon R5 M255		16000 MB/sec
	Difference: 144000 (900%)

Texel Rate

The Radeon R9 M390X should be quite a bit (about 392%) better at AF than the Radeon R5 M255. (explain)

Radeon R9 M390X		92544 Mtexels/sec
Radeon R5 M255		18800 Mtexels/sec
	Difference: 73744 (392%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon R9 M390X is a better choice, by far. (explain)

Radeon R9 M390X		23136 Mpixels/sec
Radeon R5 M255		7520 Mpixels/sec
	Difference: 15616 (208%)

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 (counted in MB per second) that can be moved over the external memory interface in a second. The number is worked out by multiplying the card's interface width by its memory speed. If it uses DDR type memory, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This figure is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better this number, 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 amount of pixels that the graphics chip can possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.