Temperature going through the roof

Qubes 4.0, Lenovo X270

Sometimes my CPU temperature goes to 90 C although the qubes OS has not much to do. If shutting down the responsible domain the temperature goes down again. The same if I pause the domain. After a while I found out that it only happens if not the first firefox browser tab is activated. In other words, if I make sure that always the first firefox tab is activated (and not the 2nd, 3rd …)before switching to another domain then I don’t run into temperature issues, but if I forget the machine is getting pretty hot. I tried it dozens of times in the meantime and always the same. Anyone having similar issues or is this a known bahavior or bug?

No, this is weird, poissbly one of your firefox addons going havoc.

But anyway 90 C under load indicates that your heat pipe either requires cleaning or some new cooling lotion.
Most CPUs shut down at 95 C to avoid permanent damage.

I think the X270 has a Skylake with Intel HWP. This is a non-trivial fix and might not even work, but you could try installing R4.1 and then building the experimental HWP patches. They made a huge improvement for me in thermal management with my i5-8365U.

Discussion on Qubes Issues, with patchset built against Xen head: CPU Frequency Scaling Broken · Issue #4604 · QubesOS/qubes-issues · GitHub

Patchset for Xen 4.14.1, used in R4.1: qubes-vmm-xen/patch-xen-pstate.patch at hwp · dmoerner/qubes-vmm-xen · GitHub