HA Yellow high CPU temp with CM5 | Home Assistant | Page 1

sonic patio Jun 13, 2025, 8:07 AM

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Hi,

I've just replaced the CM4 in my HA Yellow with a CM5 (first revision board as I was an early adopter).

I'm using the heat sink that came with the HA Yellow and was used with the CM4. Despite multiple attempts at different thickness thermal pads, and even thermal paste, I can't stop the CPU temperature climbing above 80C under idle load.

After booting, the CPU slowly increases as though there is nothing to cool it down. I can only presume it is because the case is enclosed and so there is very little airflow - however that being the case why are others not seeing the same?

The Yellow is physically in a small room which is around 32C.

Graph attached - dips are where I've attempted to make a change to the thermal pads:

radiant sierra Jun 13, 2025, 8:14 AM

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You being in a room that is 32C could play a rather big roll in this

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The cm5 has a higher output power which does the rest

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Make sure the heatsink gets appropriately hot. If it doesn't verify your mount and thermal pads are of proper quality / recommended for this installation

crystal relic Jun 13, 2025, 8:46 AM

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idle load
Can you share a picture of the glances addon UI after opening it and pressing z and c?

sonic patio Jun 13, 2025, 9:28 AM

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The heatsink is getting hot. I've tried adding some ventilation holes to the sides of the Yellow enclosure but this doesn't seem to have helped either.

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Not sure what glances gives me, looks like it requires a server running? System monitor shows:

crystal relic Jun 13, 2025, 9:38 AM

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It allows you to see per process CPU utilization and lots of other things.

sonic patio Jun 13, 2025, 9:49 AM

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Glances info:

crystal relic Jun 13, 2025, 7:02 PM

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Looks okay to me. Back to hardware, I guess.

robust scaffold Jun 13, 2025, 9:14 PM

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My Yellow with CM5 is running at 60-65C during usual operation at about 23C ambient temperature.

#HA Yellow high CPU temp with CM5