AMD Radeon R9 M390
The AMD Radeon R9 M390 is a mobile graphics card from 2015 and positioned as a fast mid-range GPU. It should be based on the the old Pitcairn chip (e.g. in 2012 used in the desktop 7870 graphics card) and offers 1024 shader cores clocked at 958 MHz. Furthermore, 2 GB GDDR5 dedicated graphics memory are connected via a 256 Bit memory bus. The graphics card is used in the Apple iMac 27-inch late 2015 (mid range model).
The performance of the Radeon R9 M390 slightly above a Nvidia GeForce GTX 960M or 870M but still beyond a desktop Radeon R7 370. Therefore, demanding games of 2015 may only run in medium settings at up to full HD resolutions fluently. The native 5K resolution of the iMac or even the perfectly scaled 2560x1600 will be definitely too much.
|Radeon R9 M300 Series|
|Pipelines||1024 - unified|
|Core Speed||958 (Boost) MHz|
|Memory Speed||5460 MHz|
|Memory Bus Width||256 Bit|
|Max. Amount of Memory||2048 MB|
|DirectX||DirectX 12 (FL 11_2), Shader 5.0|
|Transistor Count||5000 Million|
|Features||DirectX 12, OpenCL, DirectCompute 5.0|
|Date of Announcement||09.06.2015|