I found this workaround and applied it to my Dell Inspiron 3551 (purchased with Ubuntu pre-loaded, but currently running Linux Mint 19.1 (Tessa)
Source: https://easylinuxtipsproject.blogspot.com/p/bugs.html#ID25
Random freezes on Intel-based computers
25. On certain hardware combinations with Intel CPU’s, you can experience random freezes of your system. In particular the Bay Trail series of Intel CPU’s is known to be affected by this.
(The Dell Inspiron 3551 fits this description exactly.)
This can often be solved by sharply reducing the maximum sleep state of the CPU when idle (maximal C-state). Namely from 6 (or 9) to 1.
The price you pay for that is some extra power consumption, which is of course rather annoying for laptops (you’ll notice a somewhat higher battery drain speed). But at least your machine should run stable now.
Proceed like this:
a. Launch a terminal window.
(You can launch a terminal window like this:Â *Click*)
b. First check your current max C-state. Use copy/paste to transfer the following command line into the terminal:
cat /sys/module/intel_idle/parameters/max_cstate
Press Enter.
The output will probably be 6 or 9.
c. Now copy/paste the following line into the terminal, in order to edit a settings file:
xed admin:///etc/default/grub
Press Enter.
d. Delete this existing line:
GRUB_CMDLINE_LINUX=””
Replace it by this line (use copy/paste to transfer it):
GRUB_CMDLINE_LINUX=”intel_idle.max_cstate=1″
e. Save the changes and close the modified file.
f. Then execute this command line in the terminal:
sudo update-grub
g. Reboot.
h. Check the change with this command:
cat /sys/module/intel_idle/parameters/max_cstate
The output should be 1 now.