amd and a 1080 ti should work without any problem.
i read a few posts saying that ryzen cpus are very fuzzy about memory compability and can cause crashes. any other ram to try with?
some solved the problem by changing the energy Power settings to high performance.
are you using the latest version of windows? seems like alot of people had issues with ryzen cpus and windows 10 causing crashes.
i would look at the bios settings for the ram and possibly try new ram and get the latest version of windows on usb stick and try installing it one more time.
also you could try go into bios and try load default settings . reboot and try again. this fixed issues with windows 10 for some.
some people with same problem as you
https://community.amd.com/thread/231289
https://www.reddit.com/r/Amd/comments/8b0304/windows_10_random_freezes_on_ryzen/
the thing that seem to solve it for some people is checking the ram compability or changing the Power plan in windows to high performance instead of amd ryzen balanced plan.