Why do my Mac Pro fans take off like jet engines after a "Sleep" ?

[ggalaximm]

This question has probably been asked and answered a lot.

Right after I post it, I'll go searching for the answer, and add the answer to this post.

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Whether I've used Snow Leopard, Lion or Mavericks, my Mac pro tends to run the fans "like a jet engine" after I have awakened it from a "Sleep" low-power shutdown by touching the keyboard.

Why? Software error, or hardware problem, or both, or other??
[doublepost=1550875477][/doublepost]close, but no cigar:

https://forums.macrumors.com/threads/macbook-pros-fan-runs-unusually-loud-after-sleeping.1454925/

 

[handheldgames]

I use macs fan control and see the same behavior on a 5,1.

 

[MarkC426]

I don’t know why it happens.
It very rarely happens on my machine.

It does occur if I leave iTunes downloading purchases, or Daz3D rendering and for some reason it goes to sleep, even though something is active.

 

[astonius86]

My 2010 5,1 does this too. Not every time, but most times. I assumed it was normal, but maybe not? I don't have any sort of fan control installed.

 

[crjackson2134]

I've seen many odd behaviors on my machine lately, but this is one that my cMP has never exhibited. I guess the chips fell in my favor for once.

 

[handheldgames]

I should clarify... This happens on the 5,1 with a dual processor tray. I don't see this issue with a single cpu tray in the 5,1.