Server squealing around 9k hz

Mitch117 · October 17, 2023

I recently built an Unraid server and I'm having problems with it producing a squeal around 9000-9500 hz. I was transitioning from having just 4 drives to more.

This is in an ASRock N100DC-ITX (powered by a 90 watt brick - power consumption is around 25 watts with the 9300-8i). Spinning drives are powered by another PSU.

The motherboard has a PCIe 3.0 x4 slot.

I've tried with a LSI 9300-8i (x8 card) and it produces the high pitch sound.

With a LSI 9207-8i (x8 card) it's a lower pitch sound.

With a 4-port Vantec Raid card (x4 card) and there is no sound.

If I put the 9300-8i in my computer (full slot) there is no sound coming from the card.

I removed everything from the case to help determine where the sound is coming from. I think it's coming from the HBA card(s) or at least very near. The 9207-8i seems like it's coming from the processor with the heat sink on it.

Is there anything I can do to stop the noise?

Thanks.

Jarsky · October 17, 2023

It might be more likely to be coil whine from your PSU which will be dependant on the kind of load being placed on it.

I have an old OCZ PSU which was terrible for this; depending what load the GPU or other cards were putting on the rails. Hot glueing the coils helped to suppress it, but ideally better to swap the PSU if this is the case and its getting annoying.

There arent really any components on the HBA itself that should create the sound (except perhaps the RAID variant with the Super Capacitor that replaced the traditional cache battery), its all transistors, and resistors, etc....

It could explain why it doesnt make the sound in your main PC. I'd try and test with a PSU swap out if you can.

Mitch117 · October 18, 2023

The N100DC-ITX is a 19v DC powered motherboard, the power comes from a laptop brick. I've thought about trying out a different laptop brick, thinking maybe the power isn't as clean...this one is a Walmart branded 90w universal.

Prior to purchasing the HBA cards and secondary power supply, the 90 watt brick was powering a Vantec 4-port Raid card and 4 hard drives running, which averaged around around 55 watts. Now with the HBA and secondary power supply connected to the hard drives it only consumes around 25 watts from the power brick.

In my isolation testing outside of the case, I didn't connect the secondary PSU as well as any hard drives. I limited it to just having the motherboard with the HBA plugged in (no drives connected), one NVME and one flash drive for Unraid and No fans plugged in.

I took a stethoscope with just the tube to try to narrow it down and the sound seems to come mostly from two areas

1) At the PCIe slot circled in red below and

2) On the HBA card between the heat sink and the PCB (The HBA's processor?)

Those line up one over the other, so I'm not sure if I was just picking up the same sound.