I work at a small MSP and this is an old clients retired server, dell t320 - nothing special but it lets me run a hyper V server for learning Active directory without bogging down my workstation. Anyway, upgraded that horrendous fan to a nice one for $10 off Amazon.
Holy crap what a difference. It went from sounding like a jet engine when turning on and you could hear the fans from the hallway (I'm at the front of the office) to I didn't even know it was on until I remoted into it and it's sitting right next to me on the floor lol.
Thanks to an earlier post about someone who did this exact thing and gave me the green light to do it. I can't express how nice and quiet it is again at my desk now and I've got a physical server to play with!
The CPU is not going to be adversely affected by the airflow change at all. Even at 100% usage that airflow is plenty for that heatsink for the CPUs that even can be installed in that.