So I just recently got a secondhand CPU from a friend (i7-6700k) because mine died. I just installed it and the temps are spiking really bad (90C+) while idle. I've reapplied the thermal paste (2 different pastes) and made sure the cooler is on right 2 times now.
Here is a screenshot of the spikes View: https://imgur.com/a/Cta7KOZ
Here is a screenshot of the spikes View: https://imgur.com/a/Cta7KOZ