I wanted to see if anyone knew whether the Intel i5 NUC's are in a representative idle state while in the BIOS?
Based on my experiments, I am thinking that when it is in the BIOS, any power saving features of the CPU are disabled making the CPU run hotter than it would be even under moderate load inside the operating system.
I am running Debian Linux and have lm-sensors installed and ran through the sensor detection tool, and I believe I was able to get accurate core temperature. However, I see the BIOS temperature is routinely about 10° higher than it is when I am in the OS.
However, I see a pattern that suggests they are both accurate and that the CPU actually gets hotter in the BIOS. When I am in the OS, I will see it idling at around 42°C. When I reboot and go into the bios, it will be around 52°C, and over the next 10 minutes, it will rise to over 62°C. When I get back into the OS, it is back down to the mid-to-low 50's and then slowly gets back down to 42°C.
This is very similar to when I run a high load application. I noticed that temperatures can jump in a manner of seconds about 10° worth, and slowly rise after that. As soon as the high application program is terminated, it will drop 10° in a matter of seconds, and slowly go down a bit more. Since there is a 15 to 30 second span of time between being in the OS and being in the bios, it seems that it is reasonable to assume that both the BIOS and the OS temperatures are accurate. Especially given the pattern of a 10° jump, with an additional 5 to 10° slow increase when going into the bios, and the opposite situation when going into the OS.
so what I am wondering is:
1. Is my understanding correct, and that's the CPU is actually more efficient when it is in the operating system, and that the bios just has it running at close to full load? In which case, the temperature reading in my operating system is accurate?
2. Or that the bios represents a true idle state, and that the numbers I see in my operating system are 10 to 20° too low (I.e. They are inaccurate).
Any insight would be greatly appreciated. Thanks!