New CPU fan really loud at start up

[DL-zz]

I just built my first computer. Every part of it is new. However, everytime i start up my computer the CPU fan makes a really loud noise and then gets quieter after about 1 second. I opened my case and saw the fan was going really fast at start up and slows down afterwards.
I have a i5-4690 cpu
Z97s motherboard
and 750w psu

Can someone please help me figure out what the problem is?

 

[Supahos]

No issue a lot of boards spin fan at full speed at boot to ensure it doesn't overheat before it can monitor temps

 

[DL-zz]

No issue a lot of boards spin fan at full speed at boot to ensure it doesn't overheat before it can monitor temps

thanks for answering so quickly =)
Now i have nothing to worry about