I have a couple of servers with S5000PSL mb's equipped w RMM2 management modules. I keep seeing under System Health, Monitor Sensors, P1 Temperature Readings like "-40 degrees C". Surely the temp is not that cold... Does this actually mean "+40 degrees C" ? or "100 -40 degrees = 60 degrees C" or what? One board has big Noctua cpu coolers and reads "-40 degrees C " under full load. The other board has stock Intel cpu coolers and reads "-23 degrees C" under full load. This suggests to me that the former board is running cooler, and the actual temperature is like 70-40 = 30 degrees C. No?
Answering my own question courtesy of the Intel chat: The Temp reading is "relative to set threshold", which appears to be 65 degrees C. Indeed the Noctua cpu coolers are keeping the xeon procs 15-20 degrees C cooler than the stock Intel 2U coolers.