ML120/ML120 Pro fan noise?

Greetings to all.

 

I have a system here with 4x ML120 fans (the ones that came with my H100i Pro coolers) and 2x ML120 Pro fans (additional purchases).

 

Two of the ML120 units are hooked up to an H100i Pro cooler, while the other two ML120 Pro units are hooked up to another H100i Pro. The remaining ML120 fans are connected to my motherboard (using 4-pin PWM fan headers).

 

The system seems to work well, but I've noticed a... sharp buzzing/ticking noise? I believe it's emanating from the fans since it seems to throttle up and down in volume with the fan speed. The system is very quiet otherwise, except for this fairly high pitched buzzing noise that appears to be coming from the fan rotors. It's definitely not the H100i pumps as the noise does not change regardless of what RPM the pump itself is running at (be it 1K RPM or 2K RPM).

 

Is this normal for the ML120/ML120 Pro fans? It seems the worst around 700-900 RPM. Down near 300-400 RPM, it's barely noticeable, and anywhere past 1000RPM is typically drowned out by the dull whooshing noise of moving air. If it wasn't for that, the system would be very pleasurable to be around, but the noise is kinda getting on my nerves a bit since it's a very pronounced thing that kinda pierces through the air.

 

I guess if it's normal, then there's nothing I can do about that (I'm actually migrating away from a Mac Pro right now, so this has been my first PC build in well over 15 years). I'm just wondering if this is something I should be contacting support about or not.

 

Cheers,

-CMPX

Hard to say. The bearing on the ML is different than traditional oil/socket types. It uses current to balance the fan. Current can create a buzz. Some users in the past have complained about some low level noise when using large numbers of ML. It’s not something I notice with 2-3 fans. 6 or more may be something else. I suppose case design and fan location plays a factor. Also some people are just more sensitive to certain frequencies. I do not typically recommend the ML series for the “zero noise, silent PC” crowd.

I too have both ML120 and ML120Pro, and I have zero noise on my fans - other than air movement noise, of course. Try to run them disassembled from your devices, so you can spin them 360 degrees and find out 1) if they are producing any noise and 2) which angle they provide noise. Maybe it is something hitting the rotor or the blades.