Three things could cause this so you can check them.
1. Mounting of the CPU cooler - it should be very tightly held down on top of the CPU chip. If it is loose or tilted, or can be moved easily by hand, it is not making good contact with the CPU to remove heat.
2. Some CPU cooler systems arrive with a thermal paste pre-installed on the heatsink face and protected by a thin plastic film over it. You MUST remove that plastic film BEFORE mounting the cooler unit over the CPU chip. Did you do that? Or, if yours did not have that, did you install thermal paste yourself following the maker's instructions? To little OR too much can cause a problem.
3. In BIOS Setup (see manual p. 3-25) the normal configuration is to set CPU Fan Profile to Standard. If you set it to Turbo for max cooling, your fan will always run full speed. Check how this is set and change if necessary, then Save and Exit.