Full Loop Pump Speed. 100% Max or custom?

Rhaos · 6 Jan 2022 at 11:35

Hi all

Finally have my full water cooling build up and running.

Quick question on Pump/Rez combo speed. Should I be running it at 100% maximum RPMs? Or Should I be setting it lower i.e. 50%

I've read many conflicting posts, some say to run at 100% others say 35%.

Thanks in advance.

ttaskmaster · 6 Jan 2022 at 12:15

My old D5 I just had at 100% all the time.
My current one goes off an averaged component temperature curve and is quieter as a result... but it's also a fancy AquaComputer one, so I like showing off all the bells and whistles of what it can do.

therealdippy · 6 Jan 2022 at 12:24

Flow rate has a marginal effect on water temperature in relation to fan speed, but it does help. For most people the conflicting issue is noise. Those who have suggested about 35% have probably done so because of noise.
FYI my pumps idle at about 30% and I can't hear them. I use a water temperature sensor to ramp them up to about 50% at 40C when they are a bit louder but so are the fans. My tests show that this reduces the peak temp by only about 1C, but that allowed me to change the fan curves a bit to optimise the noise.
I think my 40C target is arbitrary and I suppose I could let it go higher and reduce the noise from the fans and pumps, but for now I'm happy with the noise level during gaming, which is about the same as my previous air-cooled PC was at idle!

If you keen enough to optimise your pump speed for your taste, you need to run tests to measure noise and temperature.

Rhaos · 6 Jan 2022 at 15:07

Thanks for your input chaps, much appreciated.

I'll try running at 50% and see how I get on. Running at 100% I can hear the pump make what I can only describe as a bee hive low level hum, which I've only picked up on yesterday and I wasn't too sure if I set the pump to a lower speed would it decrease the performance of the loop and if temps would go up.

Mcnumpty2323 · 6 Jan 2022 at 16:37

Yeah as others said
There's very little if any gain over a certain %
And every body has different hearing
Sometimes I prefer a set %
Rather than it altering itself up and down
As sometimes as it goes up through a certain %
It makes an audible noise
Yet as it reaches a higher %
That noise disappears
Either it's resonating at that % or my ears are more
Susceptibile to that frequency
Bottom line is I wouldn't worry about what others do
Adjust it to what works for you

MikeTimbers · 6 Jan 2022 at 16:55

I run all my DDC pumps at full speed and can't hear them. My D5 Varios run at 4 not 5, whatever that means.

Hakanese · 6 Jan 2022 at 21:03

Like Mike and McNumpty I run my 2 D5s at 80% to keep them quiet, loudest thing in the system is the crappy rgb fans for the lighting

Drumroll · 6 Jan 2022 at 21:26

No reason to run at 100%, unless necessary.
I always find the balance where the pump runs at the highest RPM yet being quiet. Some D5 were quieter at 60% than at 50%. Best way to play around, in 5% intervals, and when you find the pump quiet, run some tests to check if the loop isn’t struggling for flow.
Depending on your rads and blocks, anyway.
Triple EK (2 pe 360 and 1 xe 360), 3090 ek waterblock and active backplate plus EK monoblock (Asus X570) and a flow meter. A single D5 at 60% was fine. No improvement going faster, maybe 1C.
When tried triple Corsair 360 30mm rads, same blocks, the pump at 100% struggled. A DDC 3.2 was too loud at 80% and just about coping with the loop. Dual D5 at 60% was enough. my point, depends on your loop, but unless very restrictive, a single D5 at 50-60% should be very close to its optimum performance at a dead quiet noise.

Gavster · 6 Jan 2022 at 22:47

I run mine at around 2250 rpm, I ran it once in a gaming session at full tilt 4500 rpm and it made no discernible difference to my water temp so I can`t find any reason to run it at 100%.

Grim5 · 9 Jan 2022 at 22:36

I run mine at 100%, I get a 2-3c difference in water temp between 50% speed and 100% speed

Disco_P · 10 Jan 2022 at 16:30

I run my D5 Vario on the lowest speed otherwise I can hear the vibrations it induces into the case.

im4gine3 · 11 Jan 2022 at 10:19

i used to have my D5 at full speed since it was quiet either way.

For my DDC, i have mine set to 40% idling. They produce a whiney sound after 45% which puts me off and settting the speed from 60%+ made no difference, so i range my DDC from 40-60% static (not via pwm) depending on workload

GilesGuthrie · 12 Jan 2022 at 16:21

Mine has an audible resonance at around 50%, so I have a curve set which holds it at 60% until the CPU hits 65 degrees. It then ramps over the next 10 degrees to 100%.

pastymuncher · 12 Jan 2022 at 18:47

Due to having a massive loop I have both my D5's set to 5 and they are silent, they do sit on foam though. Seeing the amount of turbulence in my reservoir I shall be turning them down a notch or two at my next rebuild.