So far I've used a laser thermometer and found that the reading on HWMonitor are about 10 degrees higher than actual, i've gotten an old ,
Dont forget that the point at which the HWMonitor software is getting the information from is on the MB and not from the CPU, CoreTemp is the sensor on the processor itself while CPUTIN is the motherboard CPU temp sensor.
Did you ever get around to trying another PSU.
I've talked to multiple people that claimed to be professionals, one of which tried to charge me him "reinstalling windows"
Only a "professional conman" would even suggest reinstalling Windows to fix a hardware issue