[SOLVED] Whiney 40 mm PCH fan - will dampening foam help?

[mikewinddale]

I have a Phanteks Enthoo Pro 2 case with the tempered glass side panel, a slew of Noctua 140 mm and 120 mm fans, and a Supermicro M12SWA-TF motherboard.

The Noctua fans are all virtually silent, but the motherboard's 40 mm PCH fan is whiney. And it spins at a constant RPM, regardless of temperature, and there's no setting available to make it temperature-sensitive. Supermicro says modifying the fan will void the warranty, so there goes replacing the fan with a Noctua 40 mm, or relocating it to a PWM header.

Does anyone have any ideas about what I could do about that PCH fan?

I've considered replacing the glass side panel with a solid panel, and then installing noise-dampening foam on both side panels. But every other side - top, bottom, rear, and front - is full of cooling fans, so only the sides are eligible for foam.

Does anyone have experience with noise-dampening foam? Will adding foam to just the side panels have any appreciable effect on the noise of a whiney 40 mm fan? Is it worth the time and effort, or should I just wear some sound-insulating headphones? Thanks.

 

[JohnBonhamsGhost]

Will adding foam to just the side panels have any appreciable effect on the noise of a whiney 40 mm fan?

there's really no way to tell without experimenting.
the noise could be just as loud coming through the top, front, rear, etc.
maybe first try propping a pillow or some regular styrofoam against the side panel and see if it actually helps much?

Supermicro says modifying the fan will void the warranty

but, what exactly would be considered modifying?
if there is an accessible header, you may be able to just unplug it without removing heatsinks or detaching the fan.

if you have good enough airflow through this area, the temperature difference minus the fan could be very minimal.

 

[mikewinddale]

there's really no way to tell without experimenting. . . . maybe first try propping a pillow or some regular styrofoam against the side panel and see if it actually helps much?

Thanks. And good idea. I'll try that.

but, what exactly would be considered modifying? if there is an accessible header, you may be able to just unplug it without removing heatsinks or detaching the fan.

Well, there's a special header on the motherboard labeled "PCH", and changing the fan profile causes every fan except the PCH fan to change RPM. So it's apparent that this is a unique header.

I'll admit that I didn't ask Supermicro whether plugging the PCH fan into a different header would void the warranty. But they did say that replacing the fan with a different one would void the warranty. And given that the PCH fan is plugged into a special header, it seemed obvious to me that plugging it into a different header was forbidden. But maybe I'm wrong. So I'll go ask them.

if you have good enough airflow through this area, the temperature difference minus the fan could be very minimal.

True. I've got 2x140mm front intakes, 2x120mm bottom intakes, 2x140mm top exhaust, and 1x140mm rear intake (note: rear intake, not exhaust).

But I'm afraid I'm not sure what is the best way to stress-test the PCH. I tried running Cinebench, AS-SSD, and Kombustor (GPU stress) all at once, to try to stress the PCIe bus as much as possible. But I'm not sure if that's an adequate stress-test. I'm hesitant to modify the PCH cooling unless I'm sure I've adequately stress-tested it to ensure it won't exceed the safe temperature.

Also, although my SSD is PCIe 4.0, my current graphics card is PCIe 3.0, not 4.0. So I'm afraid that I might not be stressing the PCH to its fullest. Although I suppose that maybe that just means that when I upgrade my GPU, I need to re-test the PCH temperature anew?

 

[JohnBonhamsGhost]

Well, there's a special header on the motherboard labeled "PCH", and changing the fan profile causes every fan except the PCH fan to change RPM. So it's apparent that this is a unique header.

my ASUS board has a VRM HS header next to the CPU power connector, but it's just a regular 4pin PWM.
it also seems to be a type of special header but still allows regular PWM control for any fan.
shows up with non-editable image and name in BIOS & ASUS control software.

the 5-6 recent onboard PCH\VRM fans i've encountered usually use a very small 2-3 pin header that has no manual speed control.
most of them have been annoyingly loud.

last one i worked on we replaced it with a 40mm Noctua-A4 that was totally silent at full speed.
but had to use a regular fan header vs the special tiny one the previous fan had used.
actually dropped reported RAM and motherboard temps a few °C.
though this required removing the board's heatsink and breaking some of their sticker\fastener\security tape.
i imagine that's one of the ways they would determine if a board has been "modified".

two of the others i just unplugged and left them disabled with no perceptible temperature increase.
was able to accomplish without noticeably modifying anything, just reached under the heatsink with forceps and unplugged.

 

[mikewinddale]

I just looked closer, and you're right: it's 3 pins, not 4. It looks like a regular 3 pin, not something proprietary, but still, I'm not going to get PWM out of that.

It's also not a normally shaped 40 mm fan. The heatsink is square, with a circular cutout, and the fan is embedded within the heatsink. Here's a picture, taken while the fan was in motion:

https://imgur.com/a/MAYOxOK

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

But I'm not going to risk replacing the heatsink and voiding the warranty on something this expensive.

Also, the heatsink is right next to the PCIe slots, and a taller heatsink would make half the slots unusable anyway.

 

[Paperdoc]

I am sure the fan is intended to run full speed all the time. The PCH unit does a fair amount of work. It is common to have a dedicated component cooling fan run full speed always to ensure good cooling always, even if that means over-cooling on light workloads.

Further, I can understand why altering that fan would void a warranty. To alter it you would have to ensure the replacement WILL deliver at least as much air flow as the original, bearing in mind the resistance to air flow inherent in the flow path though the heatsink fins. It would be easy to get that wrong and leave the PCH with inadequate cooling.

Is this a new system, or has it been in use for a few years? What you describe MIGHT be just the result of worn fan bearings on an older fan. In that case, the right solution would be to get an exact replacement unit from the mobo maker to preserve the right cooling and maintain the warranty.

 

[mikewinddale]

This is a new system. It's a Supermicro M12SWA-TF for the ThreadRipper Pro WRX80 platform.

Just to clarify, the fan isn't exactly loud. Right now, my phone - sitting on top of the chassis - measures 38 to 40 dB, while ambient noise in my house is about 33 to 35 dB.

This computer's noise - 38 to 40 dB - is with the following fans:
1xPCH
6x140mm Noctua
2x120mm Noctua
1xPSU

The Noctua fans are PWM and set to go as low as 50% PWM when the temperatures are low enough. Right now, the Noctuas are all spinning approximately 500 RPM. The PSU is set to turn the fan off when the load is less than 40%, and right now, the load is 23%, so I assume the PSU fan is idle, though I can't see it to be sure.

So at idle, my computer is adding about 5 dB to ambient noise.

That's probably not terribly loud. I think it's just slightly annoying because the small fan's noise is high-pitched, even though it isn't loud per se.

Incidentally, in case anyone is curious: the Noctuas are great on the ThreadRipper Pro 3955WX (16 cores). I'm using the NH-U14S TR4-SP3 heatsink with one CPU fan (forgoing the option to install a second CPU fan), plus I installed a 140mm Noctua as rear intake to blow directly on the CPU, plus 2x140 mm as top exhaust. The peak load temperature under Cinebench R23 is 77.0C, well under the thermal overload of 95C.

 

[Kreil]

Thank you for the detailed description of the problem. I just got my Supermicro M12SWA-TF and the whiney chipset fan is driving me nuts. It's not just the level of the noise but the actual rather high pitched frequency that comes from the 5000+ rpm fan. I also have Noctua fans in the rest of the system.

I have tried unplugging it, with the effect that the other system fans immediately spin up - so that's not helping.

Have you found any remedy to the issue?

While a replacement heatsink cannot be much higher due to the adjacent PCIe expansion slots, there is plenty of space besides the heat sink in several directions, so it shouldn't be impossible to fit a larger heatsink with a larger diameter fan. Has anyone perhaps seen a better solution on other WRX80 chipset motherboards?

 

[mikewinddale]

I haven't found a better solution yet. But I'm planning on trying to line my case as much as possible with noise-dampening foam to see if that helps.

 

[USAFRet]

I haven't found a better solution yet. But I'm planning on trying to line my case as much as possible with noise-dampening foam to see if that helps.

Noise dampening foam can sometimes retain too much heat inside, and increase the fans RPM.