Board: ProArt Z490-CREATOR 10G
BIOS: ver. 607
OS: Win 10 Pro 2004 & Ubuntu 20.04 LTS
Issue: Whenever I do a cold start (power-on after shutdown / Power State S5 - fast boot / fast startup are disabled), one CPU core is maxed out by ACPI.sys i.e. system interrupts (/sys/firmware/acpi/interrupts/gpe6F on Linux). This is both the case in Win 10 Pro and Ubuntu.
Workaround: do a restart i.e. reboot of the system or enter the BIOS at start-up and exit the BIOS again, saving changes OR switch off PSU (G3) completely.
Troubleshooting steps done, all with no effect:
- reset BIOS to recommended options
- disabled/re-enabled fast boot in BIOS
- altered POST delay in BIOS
- updated latest drivers (probably not an OS isssue, as both Win 10 and Linux are affected)
- disabled unneccessary devices in BIOS
- disconnected everything except RAM, CPU, GPU, system disk and USB keyboard/mouse.
I built my system some weeks ago and updated to the latest BIOS 607 in the progress, so I can't tell if old BIOS versions were affected, too. Unfortunately I cannot get hold of older versions. System wasn't overclocked at any time. I noticed it first when running a benchmark and had high background CPU reported...
Anyone got an idea how to mitigate or does observe the same issue? It seems like something gets stuck when the board resumes from power state S5, but not on a restart via OS and not from global state G3.