Question ELI5: Why does speedfan slow down my fans?

[pleyland]

I'm just wondering why my PC with windows 10 blasts it's fans really loud until I simply start up the speedfan application. When I open speedfan it says some of my temps are from 50 to 70 degrees, but then within a minute it cools down to 40 degrees and the fan goes silent. Is speedfan tricking itself into thinking my PC is cooler than it actually is or does windows think that my PC is way hotter than it actually is?


Mobo: ASUStek m5A78L -M LX V2
GPU: Gigabyte AMD Radeon HD 7770
RAM: Vengeance 32gig
HD: X2 samsung EVO 250gig
PSU: Corsair CX500
OS: Windows 10 professional
Not sure what Chasis I have but I tend to keep it open. There is a fan at the back of the chasis connected to the motherboard, a fan over the cpu heatsink, and 2 fans on my GPU

 

[Lutfij]

We will need more information. Can you please list your specs like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

Include the make and model of your fans and how they're connected to your motherboard.

 

[pleyland]

We will need more information. Can you please list your specs like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

Include the make and model of your fans and how they're connected to your motherboard.

done