CPU running incredibly hot.

Hello,
I've recently been having problems with my i7 6700k CPU. Its temperatures are being registered as incredibly high. On just the BIOS screen it is idling at 75+ Celsius. Under load it has been reaching 85-100 Celsius. My Graphics card sits at around 40-50 Celsius when idle, as does the motherboard. Graphics card when under load rarely wanders above 70 Celsius.

I also do not overclock my CPU. It is running at its stock values. I even attempted to downclock it to see if that would lower the temperature, but to no avail.

Would a CPU operating at these temperatures inhibit performance at all? As I have noticed no such impact.

I am unsure of what could cause this issue and so decided to wander in here to look for help.
Thank you all for your time.

It's a desktop. Cooler is a H80i V2. It's atop my desk in an office. I moved everything into a new case a few weeks ago, so it was thoroughly cleaned then. The new cooler was installed a little over a week ago.

The 75+ Celsius value is from the BIOS screen itself - that's the CPU when idle. As for the other values, they've come from Speccy, iCue, Intel Extreme Tuning Utility, and HWMonitor.