You should try running powertop on it. It will scrape sysfs and look for things that seem misconfigured, and suggest changes to fix them. On one of my machines it enabled some peripheral power saving mode that made a pretty dramatic saving!
(I also heard that it sometimes suggests power saving modes that are usually switched off for a good reason, like apparently you really don't want some USB controllers going into certain sleep modes as they take seconds to come back).
It's a server motherboard, not a consumer motherboard, so it doesn't surprise me that power management is not great. AMD Rome is also not exactly known for its low idle power.
Looking at powertop, the various qemu virtual machines have high events/sec compared to host processes. There are also a couple of timers - tick_nohz_handler and hrtimer_wakeup - which seem to generate hundreds of events per second.
(I also heard that it sometimes suggests power saving modes that are usually switched off for a good reason, like apparently you really don't want some USB controllers going into certain sleep modes as they take seconds to come back).