Hi Ron,
My Celeron NUC is pretty much silent so I wouldn't consider loud fan noise normal. Even under heavy load I don't hear much from it. Can you compare the fan control settings on the Celeron to the i3? I'm curious to see if anything is set differently.
I have an i3 and when I started playing around with the fan control I got it to the point where it was pretty noisy. When I set everything back to the original settings it went back to being super quiet. I made the changes initially because I was concerned about overheating but I've never had a lock up or heat-related problem on either of them.
I hope this helps!
Jason