I recently purchased a Brix Gaming (GB-BXA8G-8890) with an AMD A8-5557M APU + a dedicated R9 M275X GPU.
The specifications show that 4K resolution (@30Hz) is possible when using the mini displayport output. However, I cannot get this to work with my Samsung 4K TV (UN65HU8550) with a mini displayport -> HDMI cable or passive adapter. Neither Windows 8.1 nore the AMD software show the 3840x2160 resolution as a choice anywhere.
*Note* I have an Intel PC with an i3 CPU and HD 4400 graphics that is able to output the 4K@30Hz resolution over HDMI and (normal) displayport without any problems on the same TV.
I thought that maybe it had to do with the AMD Switchable Graphics function that seems to only enable the APU for the majority of things in Windows, but even when switching to a game or program that is configured to use the dedicated GPU (with AMD's software), I cannot get any resolution above 1920x1080. I have not found a way to disable Switchable Graphics and there are no settings in the BIOS to disable the iGPU and only use the dedicated GPU.
Does anyone know if getting an active mini-DP -> HDMI cable would help with this problem?
Is there any way to disable AMD Switchable Graphics and set the dedicated GPU to be used exclusively for everything?
