I'm having the same exact issue. It started recently (like 2-3weeks ago).
I tough it was a GPU issue since i've tried 938983 differents nvidia drivers, did a clean win10 install, tried different dvi/displayport cable.. always get the random freeze while browsing the internet. Tried with Chrome, Opera and Firefox, they all did the same.
Edge and Brave browser so far doesn't seems to be affected.. but its so random that I can't tell for sure. Some times I get it 2-3times in less than a hour, some times its once 1 per day.
I even changed to a new GPU (GTX1080Ti) did a clean DDU uninstall driver + installation of the new one (411.xx) same problem.
I updated to the latest BIOS for ASUS ROG Strix X370-F... same problem.
I haven't tried the chipset on asus.com website, should I try it ?
I was told to update the chipset directly from AMD.com
Let me know if it's working out for you with the chipset driver from asus.com website.
Thanks.
PS: Specs are r7 1700x / 16gb 3000mhz / EVGA GTX 1080Ti SC BE