I know I can't get a whisper quiet CPU cooler for cheap, but the 212 is louder than I expected. I'm not sure if it's just the fan, or if it also has to do with airflow through the radiator, but there's an irritating hum. I have the 212 in stock form: the fan pulling air through the radiator. It's pointing to the back of the case, about 5 inches from the rear exhaust fan. So there could be some airflow weirdness too. With the 212 on full throttle, there's just as much air coming out the vented side as there is coming out the rear fan (all cool/moderate air, which is sweet).
When I turn off the 212, my three fan cooler master 690 II case is MUCH MUCH quieter. I am messing with PWM in my bios, but the hum just changes pitch and a bit of volume. I think it's the motor itself. So, I want to try replacing the fan. It would be nice to get a quiet PWM fan so I can still set up automatic RPM speeds. But I could consider non-pwm if the performance is better. Even if the fan turns out to be just as loud, it still may be better. Certain frequency hums can be more or less irritating to different people. Adding a nice fan will put the price closer to the Noctua UI was looking at which sucks, but it will still be cheaper, and unless something breaks