problems connecting 4 monitors to M4800 with AMD M5100

I have a Dell M4800. It came with K2100, i changed to AMD M5100.
Windows 8.1, 32 GB RAM.
All drivers are installed, games work perfectly.
The laptop rests in a PR02X dock, it has blue USB connectors, which indicate USB 3.

I have 4 external monitors I would like to use.
Asus VN279QL, Acer G225HQ, Samsung 4:3, Benq FP93G (4:3), laptop itself is closed in dock.

According to this it should work:
http://www.dell.com/support/article...h-the-amd-or-nvidia-graphic-adapters-?lang=en

I have troubles getting the monitors active.
Could you please help me understanding that note:

I currently connect the Asus and Acer via DVI using the DVI of the dual DP-DVI ports where only either can be used.
I would like to connect the Samsung via VGA and the Benq via laptop DP.

Does this work or do I misunderstand that note?



Switchable graphics in BIOS is off. Is this OK or does it have to be on for this setup?
I had troubles with my M4700 with K1000m so I switched it off, the same here.

 

I remember a peculiarity with these systems and AMD GPUs... I am pretty sure that if you want to use four external displays, three of them need to be connected by DisplayPort (two on dock, one on system). Using the DVI port that is paired with the DIsplayPort on the dock doesn't count here. If your monitors are DVI, you'll have to use a DisplayPort to DVI adapter.