The Hum...

Evil_Monkey · 12 Oct 2016 at 17:11

As some of you know I recently completed my first water cooled custom loop.

It's perfect except for the noise which has me completely stumped. It's not the pump (at least not directly), which seems quiet when I put my ear to it. Instead the noise aka 'the hum' seems to be coming from everywhere.

I assume that the pump is creating a vibration that's going through the case and creating a steady noise which is why I cant locate a source. However the pump/reservoir is mounted with foam padding (that it came with).

The noise is still present with all fans off so it's definitely a pump thing.

Is the default foam padding that ships with the D5 Photon not enough?
https://www.overclockers.co.uk/xspc-d5-photon-170-reservoir-pump-combo-wc-272-xs.html

Am I missing something obvious?

Evil_Monkey · 12 Oct 2016 at 17:30

Would that work on a side mounted pump reservoir?

The issue with hardline tubing is even a small change like this would involve a massive amount of faff.

Evil_Monkey · 12 Oct 2016 at 18:50

String said:
Lift your case off the desk/floor and see if the hum goes away.

Nope, although it does change frequency when i pick the case up. Probably because of the different pressures in the metal.

Evil_Monkey · 13 Oct 2016 at 11:55

I'll pop up a video later. It's not specifically from anywhere. I've literally gone around the case measuring noise levels and it comes back roughly the same from everywhere (around 73 decibels).

It goes up very slightly above the pump/res and below the power supply to around 78 decibels but the change in noise is barely audible.

Evil_Monkey · 13 Oct 2016 at 23:48

Ladies and gentlemen, 'The Hum':

Please don't judge me on the kink in the pipe, it will be re-bent when I have more time...

I moved the camera around to try and show the noise level next to the pump. It's not a mechanical drive as I don't have any and it's not the fans as I set them all to off for a few seconds and the noise persisted. The PSU has an eco function to switch off the fan eliminating this possibility also. It's definitely the pump making the case vibrate.

I'm going to try and alter the pumps speed per undesirables suggestion and see if it makes any difference. In theory it should...

Evil_Monkey · 14 Oct 2016 at 00:39

spiralz said:
Yeah that is quite a Hum u got there would annoy the hell out of me.

My new system had a similar issue but not quite as bad, turned out it was only when the pump reached a certain speed as it was PWM (EK Predator) I altered the PWM curve and it's gone.

Yup, that's my next port of call. Fingers crossed.

spiralz said:
Pug vs BB8 = Pug will win eventually

Yeah, he sort of did. BB8's antenna has almost come off. We don't play that game anymore.

Evil_Monkey · 14 Oct 2016 at 09:01

String said:
That sounds like the pump is running full pelt. That isn't a pwm pump is it? It's controlled by a speed selector, right?

Please tell me it's not set to 5! If it is, then set it to 1 or 2.

Yes it is a pwm pump. Tried altering the speed via software but it doesn't sound to be having any effect. I'll try manually adjusting it next.

I assume its set to 2 but it could also be 5... Not sure. Hard to reach with a screwdriver in its current position.

http://imgur.com/a/6idkO

Evil_Monkey · 14 Oct 2016 at 10:21

String said:
I don't think that's PWM and yes it looks to be at 5, which will explain the noise.

I'm an idiot. Problem solved.

I had tried adjusting pump speed but I did it via software which clearly wasn't working.

I looked at the pump setting on the pump before installation and assumed it was set to 2, but it was in fact 5.

Now at 2 and the damn thing runs almost silent.

Thanks for the input everyone.

Evil_Monkey · 14 Oct 2016 at 15:17

Greebo said:
WHy does your water bubbles not even move in reservoir in your vid though?

I'm assuming the water is flowing the most through the bottom of the reservoir which is why there are no bubbles there.

They've only stuck around higher up the res. The water itself flies through the loop (not surprisingly as it was on full whack!).

These are my temps playing gta5 (red = cpu core 1 and green = gpu).

Seems fine as far as I can tell:
http://imgur.com/a/YfXZh

CPU's a little hotter than I was hoping on stock but not exactly sure what's considered normal for an i7. Was running an AMD 8320 previously.

Evil_Monkey · 14 Oct 2016 at 17:31

Greebo said:
if thats under load its fine. They take a lot of cooling.

Yeah, get similar temps on Cinibench so it doesn't get much hotter. Will need to re-run now the pump's not on setting 5 but I'm not seeing any massive difference at the mo.

Evil_Monkey · 14 Oct 2016 at 22:10

Makes sense, I can't see how pump speed would matter much, true it spends more time heating up, but it also spends more time cooling off in the radiators...

On another note it's very weird seeing the GPU at <50.c in a game when it's whisper quiet. Beats the hell out of the 90.c I used to get with my 7970 on air. Got to love water cooling.