Temps differ greatly between different programs?

CursedSeal7

Honorable
Jul 9, 2013
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10,520
I've used coretemp for a while, and recently started using speedfan for a rainmeter plugin. The odd thing is Coretemp tells me my cores are individually at around 40c, speedfan reports that they are individually 25c. Is there something majorly wrong with either reader?

CPU is a i5-4670k stock with a Cooler Master Seidon 120M closed loop liquid cooler.
 
I have never faced a problem like this before but i can suggest you to install 2-3 different temp reader programs in order to find which one is wrong. Im now using Aida64 and HWMonitor, both are monitoring the same.