I’m running a UGREEN DXP4800 Plus with TrueNAS SCALE 25.04.2.6 since day 1 (6m ago). I’m trying to determine whether this is expected behavior on TrueNAS or if I have a hardware/firmware issue.

Symptoms

• CPU package regularly reaches 95-100°C.
• TrueNAS dashboard sometimes reports 106-110°C.
• lm-sensors reports up to 100°C (TjMax), so the high temperatures are real, although the dashboard seems to overshoot slightly.
• Average CPU load is usually only 20-30%.
• During stress tests it immediately climbs to ~100°C.

Example:

Package id 0: +100°C
Core 0:       +100°C
Other cores:   90-93°C

What I’ve already checked

• Fan is spinning.
• CPU is not obviously throttling (still boosting above 4 GHz).
• No thermal alarms reported by lm-sensors.
• TrueNAS exposes no PWM or fan control.
• No /sys/class/hwmon/*/pwm*
• No /sys/class/hwmon/*/fan*
• No IPMI/BMC.
• External room fan:
  • Blowing into the rear exhaust actually made temperatures worse.
  • Removing the external fan lowered temperatures slightly.
  • Front airflow helped a little, but the CPU still reaches ~100°C.

Environment

• Hot room (summer).
• NAS is normally inside a cabinet/closet, but I also tested it outside with more airflow.
• Changing the environment only changes temperatures by a few degrees.

My questions

1. Is this normal for a DXP4800 Plus running TrueNAS, but not UGOS?
2. Does UGOS control the fan/embedded controller, while TrueNAS leaves it on a conservative default curve?
3. Has anyone managed to control the CPU fan under TrueNAS?
4. Has updating the BIOS helped?
5. Did anyone fix similar temperatures by:
   • changing BIOS fan settings,
   • repasting the CPU,
   • or reseating the heatsink?

I’m mainly trying to understand whether this is expected with TrueNAS on this hardware, or whether I should open a warranty claim.

Thanks!