As I said above, I reckon a lot of this hinges around the USB-based video adaptors which seem to be a triumph of marketing over substance. Sounds like great enabling technology, doing away with the docking port on the laptop but the enabling technology just doesn't quite....work. They've been struggling with these USB docking station things for the best part of 5 years to my personal knowledge. Funny thing is they keep coming back for more.
It also looks like a complete spider's nest and takes a lot of messing about to plug everything in each time I "undock" my XPS15 from the PSU, USB hub, HDMI cable and USB-C/HDMI adaptor. And when I plug it all back together I frequently have to reboot to get the second monitor (the USB-C one obviously) to work. That's progress, eh.
Oh yeh - and if I maximise anything in the second monitor I get *** horizontal lines randomly flickering around the screen.
Wow!!! At last I've found this thread... Already pulling my hair for over 2 months now... And to the looks of it, it's still not fixed. I have the XPS 15 9550 + TB15 dock + 2 external monitors (dell ultrasharp u2515h).. Lid closed with the setup. Its randomly killing my DisplayPort connected monitor (HDMI keeps on working) and also got the same problem with my previous dell dock (Dell D3100) when connecting through DisplayPort... I worked for a couple of weeks but at a given point it randomly (3 to 10 minutes) switching of one of the displays. That gives me the idea that the problem at least lies in the combination of the TB15 & XPS 15... Or the XPS 15 drivers side
Will try to mess around with the closed lid option (power & battery) and will try to also work with the lid open... If somebody already figured out the solution...
REPLACE THE DELL WIRELESS CARD
Since replacing the Dell wireless card with an Intel 8265 wireless network card my 4K monitor running on a Thunderbolt 3 to DP adapter from Star Tech has been ROCK SOLID. **Must uninstall the Broadcom software in the Add/Remove programs screen.
My experience is as follows:
-Dell wireless card with output power at 100%: Thunderbolt controller resets every 5-10 min. causing the display to disconnect each time.
-Dell wireless card with output power at 75%: Thunderbolt controller resets approx. 1-2 times per hour. Clicking on a "save" option or other function that launches a File Explorer window often coincides with at reset.
-Dell wireless card with output power at 50%: Thunderbolt controller doesn't reset, but connected Bluetooth devices interfere with the weak WiFi signal and cause the WiFi connection to become useless. Must turn off Bluetooth to use WiFi.
-Intel 8265NGW Wireless-AC: ROCK SOLID. **Must uninstall the Broadcom software in the Add/Remove programs screen, it interferes with the Bluetooth driver.
flamesfan2635: for the last three months I've been managing this problem by adjusting the broadcom's power and that has worked for me 95% of the time. I go back and forth between 75% and 50% on the power output of the broadcom, depending on the setting I'm in. I have two TB15s, each with its own 4K monitor -- one at work and one at home. The TB15s work flawlessly for me with this arrangement. So everything you're saying makes complete sense to me. My only question is where did you get the Intel 8265NGW Wireless-AC and did Windows or Dell have the drivers for it?
Hi phineasjw, I purchased the Intel 8265NGW from eBay. (It was the only place that I could find the newest Intel card.) I downloaded the drivers from the Intel website. Make sure to download the drivers before removing the old card.
Any solutions yet from anyone how to avoid that Fan turns up when USB-C port is being used?
I have newest everything installed ofc
Thanks in advance for hints
9350 with 4K external Samsung through TB Startech DVI. The external screen was behaving bad with random disconnections, no driver/BIOS updates helped too much. Following the recommendations I replaced the Broadcom WiFI in my 9350 with Intel 8265.
Yes, it is solid. I'm not experiencing anymore the random 4K external screen disconnections when working with the standard office apps, etc.
But, it is not 100%. Sadly the external screen started to disconnect when I put it under the "ultimate" stress - www windity com page running on full screen. Those wind maps are driving the screen crazy.
Anyway, I guess I can live with that. 99% stable. Now that my laptop is not the "latest" model anymore..
This helped me when I had USB overload "Power surge on the usb port" error. I forgot I had a siig usb 3 port on my desktop with nothing plugged into it, so used that to connect my xps 9550 to my DVI KVM switch to share mouse and keyboard. I'd use that kvm switch to share monitors but instead getting usb-c to displayport cable as I don't want to drop from 60 to 30 fps when at 4k.