Hello,
I am experiencing a power management / standby issue on my Beelink SER9.
Device information
Model: Beelink SER9
BIOS version: SER9T407
BIOS date: 2025-12-17
Windows reports that the system supports only Modern Standby / S0 Low Power Idle
S3 sleep is not available
Problem description
When the display turns off automatically because of idle timeout, the system does not become quiet as expected. Instead, the cooling fan speed increases noticeably. The same behavior also happens around transitions into standby / low power states.
From the user perspective, the issue looks like this:
the monitor turns off after inactivity
instead of entering a calm low-power state, the system becomes louder
fan RPM rises significantly
this suggests the platform is still active or is failing to enter a stable low-power state
What I found in Windows logs
I collected Windows Event Viewer logs and SleepStudy data.
The logs repeatedly show:
Kernel-Power Event ID 506: system enters Modern Standby
Kernel-Power Event ID 507: system exits Modern Standby
Kernel-Power Event ID 40: \Driver\ACPI stopped a power state transition
Kernel-Power Event ID 42: system is entering sleep
Kernel-Power Event ID 107: system resumed from sleep
Kernel-Power Event ID 187: a user-mode process attempted to change the system power state
Most importantly, I also see this ACPI error:
ACPI Event ID 4
Windows reports that the ACPI BIOS attempted to read from an invalid I/O port address (0×40) inside a protected range 0×40–0×43
Windows warns that this may cause system instability
This strongly suggests an ACPI / BIOS firmware problem during power state transitions.
Why I believe this is a firmware / ACPI issue
powercfg /requests shows no active blockers
Kernel-PnP does not show a clear device re-enumeration problem
the issue happens repeatedly during automatic display-off / standby transitions
Windows specifically reports ACPI-related power transition failures and an ACPI BIOS error
Expected behavior
When the display turns off because of idle timeout, the SER9 should either:
remain in a stable low-power idle state quietly, or
transition cleanly into standby without increased fan activity
Actual behavior
fan speed increases after automatic display-off
standby / low-power transitions appear unstable
ACPI-related errors are recorded in Windows logs
Please check whether this is a known SER9 BIOS / ACPI firmware issue, and whether there is:
a newer BIOS version
a beta BIOS
a firmware fix
a recommended BIOS setting or workaround
If needed, I can also provide the exact Event Viewer entries and the SleepStudy report.
Thank you.
