CPU Running at max all the time

I haven't turned on my computer in a while, but when I did, I noticed that my CPU cooler is running loudly all the time. Doing some digging I found some issues that seem conflicting to me.

1. In CPU-Z, I am running at 3900 MHz all the time. When I tried overclocking to 43x, it ran at 4300 all the time.
2. In task manager processes, system idle process CPU is 99%. However, in task manager performance, overall Cpu usage is 0-1%.
3. In the bios, I have everything set to defaults except my ram which is 2400 at 1.63v.
4. In the bios, when I turn the computer on fresh, the cpu isn't over working at first, but within 1 minute the fan comes on louder and louder.

How could the system be constantly at 3900Mhz, but register as 0% usage?
What could make it overheat even in the bios - before windows has started up?

Double check you have the power savings features turned on

Like Janus suggested, check that the default "Max Power Saving" preset hasn't been changed to something like "High Performance" or "Manual".

The CPU usually runs full speed in the BIOS. Also in the BIOS make sure C1E is enabled.

Power settings, such an easy fix... Thanks!!!!