@nvs Hi there, we had a similar issue with on our 5900x boxes. We have about a twenty of these and they have been generally greats hosts for xcp loads. However, one of them was constantly rebooting. While testing the ram the temp jumped to 90/90. They are running in 1U boxes so I expect heat but this seemed silly. We ramped the fans to max but this did not help.
We then used bios to drop down various cpu boost profiles and gadgets to lower the heat and re-applied paste to cpu..
so far so good.