X399-e Motherboard keeps disconnecting external HDDs

Hello everyone,

first time here with weird troubles, hope you guys can enlighten me. So i had 4 plotters running smoothly each with Tomahawk B550 MOBO and Ryzen 3900 CPU, 2x NVMe 2TBs. Each generating 30 - 33 plots / day.
memory_buffer: 4000
max_concurrent: 7
max_concurrent_with_start_early: 25
initial_delay_minutes: 0
stagger_minutes: 35
max_for_phase_1: 3

Expanded my Plotting farm with 4 more PCs with X399-e MOBO and Threadripper 2920x CPU, 64 GB RAM and 2x 2TB NVMe. Plotting to External 5TB HDDs through 16x USB hub (same as earlier PC setups with Windows 10 and Sw4r plot manager). My external HDDs seem to be disconnecting out of thin air after an Hour or 2 randomly until there are no External HDDs available. After restarting PC - all external HDDs are visible again. Worst thing - they are disconnecting even if i’m not doing anything at all - PC is running idle.

What i’ve done for system:

  • install fresh windows,
  • run KeepAliveHD software for HDDs to not go sleep,
  • disable upnp,
  • update all drivers,
  • installed all possible MOBO upgrades and additional softwares,
  • disable USB sleep through power options,
  • disable USB sleep through BIOS.

I’m out of options guys, what should i else try to make HDDs not disconnect? I mean it’s pretty much the same setup for Ryzen 3900 PCs and Threadripper 2920x PCs. Only the CPU and MOBO is different, but all 4 Threadrippers keep disconnecting HDDs out of thin air. Thank you in advance.