I have the same issue flashing white lines (XPS 9550, UHD, SSD 512go)
It does not appears regularly, mainly when a second display screen is connected.
It was ship later last week so I suppose that bios is up to date.
Disable the intel graphics didn't solve the issue, worst it made nvidia control panel unavailable.
I wonder if I have to contact the support for a replacement or not? Is there any new for this issue ?
Thanks a lot for your help.
I love this machine but I am a bit disappointed by these issues, especially at this price...
I have just had the screen replaced after contacting Dell support.
My problem was also intermittent but would not stop once it was started.
I would contact them as you will be under warranty.
I'll let you know if the problem occurs again with the new screen.
Thanks a lot Liz,
I am waiting your feedback and there is bank holidays so there is no rush...
The issue is quite persistent tonight on my laptop...
It's been nearly a week since my screen was replaced and the problem has now gone, so it suggests that it IS the screen and not anything else.
I was also experiencing really bad shadows and inky blacks when playing videos, this has also gone now so it's back to being a top-notch screen that is worth the money!
Hope you get yours sorted soon