With Windows installed, you could get, with a reasonably good heatsink-fan unit, low to mid-40's. With a liquid cooling solution, low to mid-30's.
With no O/S installed (i.e. you are sitting in BIOS Setup), your readings could get much, much higher. The problem is that, in BIOS Setup, it is using spin loops to wait for input, so processor is staying busy. At the same time, all power management features are disabled, so a lot more heat will be generated. Eventually, after, say, 10 minutes , you are going to see readings in the 50's or even 60's.
i see.. so 40's - 50's it's normal for i7-8700 ( non K ) with original heatsink fan in BIOS mode.
because my i7-8700 is brandnew, and i compare it with my g4400 ( already 2 years and have 24's in BIOS mode without OS )
i thought it was abnormal.
i think i want to try a liquid cooling solution for my processor ( best type, last longer but not to expensive XD ).
do you have any suggestion? i really appreciate it.
idle means , still processor runs with some applications and services background continuously ,
Some manufacturers used 3D graphical user interface in the BIOS , so in this case processor gives more temperature than with running os .
I have researched on my asus laptop , bios graphics UI uses intel UI so it takes more temp than with running os
I have to say, comparing what it happening with a high-end 8th generation Core i7 processor with a low-end 6th generation Pentium processor is, well, silly.
Again, do not worry about what is happening while in BIOS Setup. Worry more about what is happening when running Windows (or Linux). Look at the temperatures when idle and when under load. You can use the Intel Processor Diagnostic Tool to test the processor. It even verifies temperatures when placing processor under load. It can be downloaded here: https://downloadcenter.intel.com/download/19792/Intel-Processor-Diagnostic-Tool.
Hope this helps,