Question AIO lowers RPM and starts buzzing until a manual restart (DeepCool LS520 SE)

[Khalamete]

Hello! I just built a PC for the first time and things went relatively well, but I'm having an issue with my AIO cooler buzzing. I have the pump plugged into PUMP_FAN1 and set to PWM/100% across all temps, and the pump fan plugged into CPU_FAN1. Everything boots perfectly and it runs quiet, but at some random point, even idle with nothing to trigger it, the RPM will suddenly drop from 3100 to 2600 and the pump head starts buzzing. It's a consistent sound and pretty loud, not bubbly, and will continue until I restart the PC manually. Temps continue to run cool and don't seem to change at all after the RPM drops; everything still running fine. I've checked all fans, manipulated the tubes, shaking for air bubbles, re-seating the AIO, but nothing. It's always associated with the exact same drop in RPM and consistent until restart. No performance impact otherwise.

Sound:

View: https://www.youtube.com/watch?v=fkzj9twMx9E

Specs: https://pcpartpicker.com/list/rmpsL9

PC and settings (album):

https://imgur.com/a/uGnchMg

View: https://imgur.com/a/uGnchMg


Had a few issues but this is the only one I haven't been able to Google my way through. Any ideas appreciated. Thanks.

 

[MrLitschel]

The AIO may have some air in it. Going by the photo, if there is air trapped the may be affecting the pump.

I would move the AIO from the side position to the top to rule air in the system. If it still makes the noise and drops RPM, the pump itself may be bad needing it to be RMA'd.

 

[Khalamete]

The AIO may have some air in it. Going by the photo, if there is air trapped the may be affecting the pump.

I would move the AIO from the side position to the top to rule air in the system. If it still makes the noise and drops RPM, the pump itself may be bad needing it to be RMA'd.

Gave this a try today, but same result. Still playing around with different things, but RMA is looking more likely unfortunately. Thanks for the suggestion.

Edit: I came across a program called FanControl that gives me manual control of the aio pump speed, and whenever it drops RPM and starts buzzing, disabling and re-enabling manual control fixes it. Just a bandage but much easier than having to reboot; takes just a couple seconds. Really weird that it's happening at all, though.

 

[AZ_Daddy]

I have this very same issue with this pump. I even sent it back for a replacement (through Amazon) and it too does this. This is on a new build PC. During most usage and even gaming it doesn't cause any issues but if I'm doing a movie encode on handbrake for instance , it causes program crashes as the temps will climb too high eventually. Did everything I could to ensure there wasn't air trapped in pump after install so I don't think that's the issue.
I'm also using fan control to turn off the pump momentarily when it happens and this resets the rpm back to 3000+ but I'm not keeping it. I ordered an NZXT AIO and once it gets here I'm swapping them out.

As a side note I had ordered the 360 version of this AIO and had it installed on the front of my case and it had zero issues with the pump. Decided to go with 240 version since I have a 4090 in a midtower and there was no fresh air pulled into the case with that rad there(top only supports 240mm). I'm wondering if the 240mm versions just have bad pumps or something.