My Dell Inspiron 15 7567 laptop with a NVIDIA 1050 ti graphic card and the Nvidia 390 driver freezes randomly in Ubuntu 18.04. It happens every 15-60 minutes.
I had the freezing problem in Windows before, but resolved it in Windows with updates, before I installed Ubuntu in a dual-boot configuration, where Windows boots from an SSD and Ubuntu boots from an HDD. Other Ubuntu video drivers have been tried, as have multiple complete re-installations of Ubuntu, but the problem persists. Reverting to factory default settings in BIOS/Setup did not solve it.
Disabling browser hardware acceleration reduces the frequency but does not prevent it. Full screen video at multiple websites (other than YouTube) reliably triggers the freeze. Switching to the onboard Intel display device does not solve it.
Windows CPU temps are typically around 30 degrees Celsius, but Ubuntu runs the machine at 50-60 degrees Celsius. I was able to reduce that to 50 by changing the speed of the fan with i8kutils, but that doesn't affect how often the system freezes.
Here's part of the log file "/var/log/syslog" from when it freezes: https://pastebin.com/t7LXGcwD