Trouble with XPS 15 9550, USB-C/Thunderbolt 3, and external monitors

Same issue here with XPS13 9350, connecting 4K Samsung though Startech TB32DP2 Thunderbolt 3.

With the WiFi ON, the Startech is recognized and appears in the Attached Thunderbolt Devices menu. The connected Samsung 4K screen lights up fine and runs full res at 60Hz (though DP2 cable). The first time I attached the screen it stayed on for probably 10 minutes before the first signs of trouble came. The attached screen started blacking out and then the Startech completely dropped out.

Now I have the same repetitive scenario - in less than a minute after starting the laptop, the attached screen blacks out, then both screens (built in and attached) start flashing for 10-20 seconds until the Startech drops out completely from the Attached Thunderbolt Devices menu. I have to plug the Startech out and then back in to get the attached screen back online, but the flashing starts almost immediately, and this goes on, rendering the setup completely unusable.

Earlier I was using a "no-brand" UCB-C to HDMI adapter plugged in the same port. The attached 4K screen was appearing (max 30Hz) and occasionally blacking out, sometimes quite often. Annoying but at least usable as opposed to the above T3 setup. I have noticed that using BT mouse/keyboard was affecting the stability of the screen link, probably the WiFi as well.

After reading though the forum I tried running the TB3 setup in "airplane" mode and indeed the screen works fine now. I reduced the WiFi to 75% but occasionally the screen flashes, so I drop the WiFI power setting further down to 50%. Still I get the 4K flash once in a while... Clearly TB3 link to the screen is not entirely stable.

For now I'm fine as I'm using another Startech dongle USB3 to RJ45 connection and running my internet through LAN cable. Once I'm out the office I can use the WiFi as nothing is attached to the TB3 port. But I don't think that should be the solution (not for a 2000$ high end Dell laptop at least). And ultimately I would like to see the external screen stable on at all times.

dell d630 my usb point are not warking

After dialing the WiFi power back to 50% the Thunderbolt connection to the Startech TB32DP2 dual display port adapter has been solid.  However, at 50% wifi power the bluetooth transceiver over powers the wifi connection and the wifi bit error rate renders the wifi connection useless.  This happens whether a bluetooth headset is connected or a bluetooth mouse.  When transferring a large file and watching the wifi in task manager you can watch the effect on throughput by cycling the bluetooth device on and off.  Turning wifi back up to 100% allows simultaneous use of wifi and bluetooth... but almost instantly the thunderbolt port fails.

I've tried all available solutions on my XPS 9350. The only way to get close to the "nirvana" is connecting the 4K screen though TB3, Startech dongle TB3 to DVI 1.2, high performance mode on the laptop and active Airplane mode. And the Wifi card power option is at 50% but that won't matter anyway, since the Wifi is disabled in the Airplane mode. 

With the above, the external screen works (almost) stable at 4K 60Hz, but at random intervals, say 10-12 min the external screen blinks which is quite annoying. I noticed that the XPS doesn't like specific web pages for example, which when opened, make the external screen to start blinking every 10-15 sec, rendering all work impossible.

Is there any update from Dell on the issue? What happened with the end of June "final solution"??

The recent drivers update (including critical video driver) seem to get my 4K @60Hz though T3 to DVI Startech dongle work solid for straight 2 days. Did Dell finally nailed it?

Looks like the last two driver updates, the firmware one for usb (TB15 has to be plugged in), and the intel video drivers solved it but I have only been testing for a few hours. I have wifi on and connected plus Ethernet in the dock. Haven't seen any hick ups and the dock doesn't seem that warm. Watched a bunch of 4k footage on youtube with my secondary monitor in the dock. Still going strong.

Besides the screen going to sleep, I had one other issue prior to this update. If I left my laptop the screen would timeout and go black, as it should. But I could never wake the secondary screen. I would have to unplug and power down the monitor. Replug in the dock and turn on the monitor. Minor issue, I hope that was solved too.

So far it's working. We will see how it is in a few days.

So after running it hard today, I found out this. 

It doesn't appear to have the screen flicker issue anymore. I turn it on, plug in to dock, and it works. For hours. 

If I leave it plugged in to the dock and put the laptop to sleep, it won't wake the secondary display. Only way to see the screen is to use the function keys and up down to an different option and hit enter, blindly. Or disconnect from the dock.

Basically anytime I have it plugged into the dock and put the laptop to sleep, the screen never wakes without switching to the laptop display. 

Keep in mind, I never shut off wifi. I had it always connected to a wifi network while connected to the dock. This caused no issues. I don't have the power decreased on the wifi either. 

Finally, I hope this is it. They may have actually fixed it. I will keep reporting as the days go by.

Heads up everyone! I was bored for a minute after I just posted and checked out the drivers on support.dell.com. Dell posted a BIOs update that looks like it is the final patch for any left over issues. Today July 5th. Here is a copy of it. I'll update my laptop and report back.

I want to add that I had another timeout style glitch. 

If I leave my laptop for 10 minutes my screen times out, and goes black. As it should. If I come back the secondary screen won't come on and I have to switch. Or the laptop screen will come on but it won't switch to secondary. The only way to get it to work again is, unplug the dock from the laptop and turn off the secondary monitor. Then turn back on and plug the dock back into the laptop. Select the secondary only and it works again.

Minor issue but it works otherwise. Finally!

I'll keep reporting. I do a lot of programming work so I'm always on my laptop.

I ran all the updates/driver/bios installs.   I am seeing issues when plugging in headphones to the WD15.  Audio works for a minute then drops.  I was running basic video testing from YouTube.  I unplug the headphones and onboard speakers work fine and video continues.  I attempted to play around with RealTek Audio drivers by using generic ones.  Now, the network drops completely and working even worse.  Tried reinstalling latest drivers again but now WD15 GIgabyte Lan drops off of device manager.

Anyone else seeing this?

Pabster1192 - Are you running the XPS 13? The topic here is for the XPS 15 9550. As I understand the WB15 is only for the XPS 13. The solutions/driver updates I mention are for the XPS 15 with the TB15 dock.

Also everyone else, there are firmware updates for the thunderbolt controller that were released July 6th (today)

Everything is running well on my end. Just the wake issue from sleep to secondary monitor. Going on day 2 without any other issues.

I also want to mention, I tried to do the most recent driver - 

Intel(R) Thunderbolt(TM) 3 Firmware Update

I have an XPS 13 with many of the same symptoms described in this thread - external screen via thunderbolt does not work do to flicker high fan (power) usage and, most significantly, the screens just cut out.

I wanted to report that dialing the wifi back as described by FLAMESFAN2635 addressed my issue as well. Does this mean the wifi range won't be as good in this situation?

For my XPS 13 you must use the thunderbolt port if you want an external display. I'm shocked Dell would allow this to persist or even expect a customer to except a $1800 computer that cant drive an external display! Worse, there customer service [sic] does not even seem to know of these solutions.

Maybe I changed my Wi-Fi since I tested this laptop at home last! I had to set the authentication mode to WPA2-PSK on my access point. (Other devices weren't as picky though.)