Radeon R5 M255 is an entry-level graphics card based on the second revision of the Graphics Core Next architecture.

It offers a core codenamed Sun PRO that packs 320 Shader Processing Units, 20 TMUs and 8 ROPs, on a 64-bit memory interface of DDR3. While the central unit runs at 925MHz and goes up to 940MHz, in Turbo Mode, the memory clock operates at 1000MHz. The regular version should offer 2GB of video memory but expect to see gimmicks of up to 4GB.
Technically R5 M255 is just a higher-clocked Radeon HD 8570M. Due to its very limited performance, even Intel's Iris Graphics Will offer better performance and so it ends up being an useless acquisition.