New threadripper desktop: random crashes/freezes

Hello,

I recently bought a new Threadripper based system and I've been having trouble with, potentially, the hardware of the machine. The system randomly crashes, seemingly at random:

1. Sometimes the crash is right after a boot; right at the lightdm login screen or right after logging in: the display freezes, I cannot jump to a tty and I cannot ssh into this machine.
2. Sometimes the crash is after a wake from sleep: the mouse cursor freezes, but I can ssh into this machine and issue a poweroff command: after which the ssh connection is closed but the screen stays on: further attempts to ssh back into the machine fail.
3. Sometimes, like in 2, the display gets corrupted with random blocks of pink colour, the rest of the situation remains the same: I can ssh into the machine and issue a poweroff command, which has no effect on the display but the ssh connection gets closed: I can no longer ssh into the machine after this.

The hardware configuration is:

• Samsung 970 EVO Plus 500GB - Solid state drive
• ASRock X399M TAICHI
• Gigabyte Radeon RX 580 GAMING 4GB
• AMD Ryzen Threadripper 2950X - Processor
• Corsair Vengeance LPX (32GB)

And I'm currently running:

Code:Linux quasar-nixos-tr 5.4.6 #1-NixOS SMP Sat Dec 21 10:05:23 UTC 2019 x86_64 GNU/Linux
I've found no reliable way of reproducing this issue and I've not been able to find anything in the logs.

Once the system has booted up, I never experience crashes for the first session after the boot: the crashes of type 2 and 3 only occur once I've suspended the system at least once.

I've also tried multiple kernel versions, none of which have solved this for me.

I'll appreciate any help.

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Edit: I recently went to the BIOS settings of this machine and found that the RAM's clock speed was set to 2933MHz while this is a 3000MHz RAM.

I've since set that correctly and rebooted the machine. But I'm not sure if that has any bearing on this issue.