Pi4b heating up

Hello. I’'m using Dietpi (8.3.1) on a Pi 4b which is passively cooled by a full body heatsink. I changed my router recently and I noticed that the Pi’s idle temp went up by ~13C while directly connected to it, either via cable or wifi. However, if there’s a switch between the router and the Pi, it’s temp goes back to the normal range.
While connected to the router directly, Pi’s idle temp is ~51C, but when connected to the switch ~38C.
How could I check what’s going on?

have a look to the process overview if there is something running.


Here’s what I get

I also checked

tcpdump -i any port not 2873

, which besides some dns requests running from time to time didn’t point me to an issue.

I uninstalled most of the software running on it, but it didn’t seem to do much. Atm I’m reinstalling the OS and will try to leave it idle and check. Then I’ll attempt to install everything back, program by program.

honestly I never have seen a system temperature increasing by the way how it is connected to a network. Usually CPU usage will have a huge impact on temps. Probably there is something causing higher load? Or does the switch is offering just 100Mbit instead of the router providing full 1Gbit network?

The switch offers 1gbps network, it’s a TL-S105.
So I’ve reinstalled the OS and the temp is 37C after 10 minutes idle. Currently installing Pihole w/o Unbound, as before. Will leave it some time idling and then move on to Docker and the rest.

I installed everything back and the Pi is behaving normally. Must be some other thing I did. Will try to backtrace the ssh commands I used over time next.

So I found out what was the problem. In order to hide the power bricks and wires from the Pi and the router, the Pi itself and it’s ssd, I used one of those round tin biscuit boxes in which I also stuffed an extension cord to power the devices. Bad idea.
When I started reinstalling everything the Pi was just outside the box, and as I finished setting everything up I placed it back inside. So the high temp came back. I also accidentally deleted 120gb worth backups… what a great weekend it has been.

Makes sense, always good to allow the SBC and attached devices breathing, or use cooling solutions to get the heat out of the case.

Hopefully you don’t require the backups now, so you can trigger new ones.