Dell XPS 15 9550 video signal drops using USB-C to DisplayPort cable

Don't mean to be funny but did it plug all the way and click? It took me a day to realise the usbc needs a click at the end u like regular usb.

Tried reducing the wifi even Down to 25% in preferences of the wifi card, didn't work I'm afraid, still dropped my usbc to DisplayPort signal on the 9550 I'm afraid, just not as often, but still enough to be impossible to work with...

I updated all the drivers and bios to 1.4.4 on a new XPS13 after failing to get the Dell WD15 docking station to work with resulting HDMI screen flickering and USB 3.0 devices intermittently failling (on the docking station).  

I started to suspect USB-C problems as the USB 3.0 on the host computer worked well and HDMI and USB 3.0 were iratic on the docking stations.

I personally tested FOUR brands of USB-C docking stations/slash adapters, the first being Dell, and they all exhibited the same behavior of interemittent operation.

I called dell...the Dell tech reverted the Windows10 instance to its factory default and worked for four hours to no avail.  They missed the follow up support call.

I'm a software delvelopment guy so I knew what I was looking at.  The Windows device manager for the Plugable DisplayLink display device can be seen loading and unloading, seemingly happy then failing.  DisplayLink is included in Windows10 now.  This behavior mimics the syptoms of the display flickering and USB 3.0 faillures.  The Plugable DisplayLink was replaced with one that had worked with an XPS13 they had and it still failed similarly.  The models I tried were:

Dell WDF15 shipped from Dell with the new XPS13

StartTech USB-C Dual Monitor (MST30C2DPPD)

Pluggable USB-C Triple display (DisplayLink Driver included with Windows 10)

Pluggable USB-C Triple display #2 (bench tested successfully by Plugable on an XPS13)

Mokin USB-C to HDMI/USB 3.0 adapter

My research of the literature on the Internet suggests some models having problems with associated wifi cards (either adjusting the power to 75% which did not work for me or completely replacing the card with an alternative brand).  My guess would be that there could be a particular subcomponent (like wifi or usb) that interfers with the USB-C components and causing the driver to fail.  If Dell did the research on support cases they may find the correlation but that requires something to think about it.  I'm waiting to see what Dell does.

I have this problem too.