I built a new computer recently and ran into hard freezes on Win 10 which occured randomly (anything between 1min and 70hrs could be between two freezes).
So as a troubleshooting attempt, I created a bootable Ubuntu USB stick (ISO file was ubuntu-20.04.1-desktop-amd64.iso). That stick ran fine on my other computer for ~10hrs but on the computer in question Linux keeps freezing after 60 minutes maximum, I had 5 freezes so far (freezes mean: screen freezing, no response from any input except force shutdown via power button or PSU and on Windows buzzing sounds from the speakers if any sound played at the freeze time, forgot to test the sound on Linux freezes though.)
The only things I did in Linux was rearrange displays, change keyboard layout, connect to WiFi, use Firefox and at two of the 5 freezes I installed smartcmd to test the SSD out of curiosity. I monitored RAM and CPU with System Monitor and there were no noticeable problems, temperature also can't be the cause.
I plan to let it run overnight with WiFi disabled (Ethernet doesn't work even though it's plugged in and worked on Windows after installing drivers) and see if I still get a freeze, but I thought I could ask for help here in the meantime.
So, my question is: Has anyone an idea what could cause these freezes? I feel it's weird the timings are so consistent with the freezes when they were definitely way more random on Windows.
I suspect a CPU/Motherboard error (i5 10600K, ASUS ROG STRIX Z490-G WiFi). I temporarily ruled out RAM (2x16GB Corsair) because it froze with both sticks one at a time and how likely is it both RAM sticks are faulty? BIOS is up-to-date etc. and I tried around with a lot of BIOS settings but to no avail so I think I've done everything I could on the BIOS front. PSU has already been exchanged.
I am using Ubuntu/Linux for the first time so I apologize for maybe missing basic knowlegde and possibly having trouble understanding your answer in advance. Any help would be really appreciated, thanks!