I'm owning a NZXT Guardian 921 casing since 2009 which comes with 3 build-in 120mm fans (rear, side and front).They are all run at approximately 1300~1600RPM according to Speedrun readings.
This morning, the rear fan made an extremely loud noise and spin at very slow rate which I believed it was failed eventually.
Now what I'm concerned is, is it fine for me to replace the failed rear fan to a new 2000RPM fan? It makes loud noise then my original rear fan once installed when the side panel casing is closed due to more airflow being sucked out of the system than usual. Also, I have a graphic card cooler fan installed.
Please advise the airflow system is doing fine or not. Thanks. :)