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Fan speed smoothing

sultan.of.swing

Junior Member

Fan speed smoothing

Saturday, March 9th 2024, 8:32pm

Is there anyway to change the smoothing for the reported fan speed RPM?
When fans are connected to any aquacomputer device the fans speed seem to have some sort of smoothing applied to them that cause the RPM readings to be extremely smooth but read lower than if you put those same fans on a motherboard header.

Methodical

Full Member

Sunday, March 10th 2024, 5:01pm

Correct me if I am wrong, but it sounds like you are trying to create a fan curve that ramps up the fans smoothly. If so, what AQ equipment do you have?
"Never be afraid to try something new. Remember, amateurs built the Ark, professionals built the Titanic"

Speedy-VI

Senior Member

Sunday, March 10th 2024, 5:33pm

What you are observing may also be due to whatever fan(s) you are using. PWM fans are not all the same. Some will spin at max RPM if there is no PWM signal, others will stop. Some Noctua fans had a non-standard PWM implementation. Some Artic PWM fans require a diode between the PWM pin and ground to function properly when connected to an Octo or Quadro PWM port.
Are you using the Power preset, Curve controller, or Target temp? The Target temp is actually a PID control loop. This mode has 5 presets but you can also select User Defined which lets you set the PID Loop parameters, including Hysteresis.

sultan.of.swing

Junior Member

Sunday, March 10th 2024, 5:56pm

I specifically use a curve controller.
But that is not my issue.
My issue is that if I connect 3 Artic PWM PST fan's to 1 port on my aquaero 6xt with the curve controller maxed out the RPM will drop 25 rpm per fan connected.
So 1 fan will read 1700, 2 fans daisy chained will read 1675, 3 fans daisy chained will read 1650.

If I connect these same fans to a motherboard header with 100% PWM the fans will all read 1700.

This is using the Arctic included wiring which only reports 1 RPM in the daisy chain sequence, I have also tested other fans like my Noctua A12x25's with proper splitters that only have 1 RPM wire connected in the daisy chain and still get the big RPM drop.

So my question is why does the Aquaero do this and not my motherboard?

I am also noticing an issue where Phantek T30's if only 3 are connected to 1 port I can only get about 2200RPM out of them instead of 3000.

Speedy-VI

Senior Member

Sunday, March 10th 2024, 7:54pm

The Artic fans are the ones that multiple people have reported problems with when connecting to the Octo or Quadro. I don’t know if it affects Aquaero. Aquacomputer said it seems to not affect all Artic fans so maybe it was a particular batch. The posts about this are on the German forum somewhere. The solution is to install a diode between the PWM pin and ground. HERE is a post about this on the Aquacomputer support subreddit. I don’t know if your fans have this issue but it might be worth a try.



Phanteks T30s – I bought a 3-pack of T30s for a future build. I have not installed them yet but I did connect 1 to an Octo to test it. I was able to get 3000RPM. I assume you are aware that you have to switch the T30 to Advanced Mode to get 3000RPM. With three of them connected to 1 port, trying to run them at 3000 RPM may be trying to pull too much current from the port. Have you checked what the power consumption is in Aquasuite when you do this? I would check the power consumption reading for the 3 Artic fans too. Maybe the port is running out of power so it is slowing down the fans.

sultan.of.swing

Junior Member

Sunday, March 10th 2024, 10:24pm

That issue is completely different to my question and has no relevence.

The big issue is why does the RPM reported drop when more and more fans are daisy chained on an Aquaero or a D5 next but the RPM does not drop when connected to a motherboard header.

As far as the T30's 6 daisy chained pulls about 27w worth of power. So on a D5 next it will fault the controller but I can run the controller at 96% and get 2900RPM.
Those same 6 fans on the Aquaero (which is rated 30w/channel) I can only get about 2200RPM out of them.
And yes they are in advanced mode.

Speedy-VI

Senior Member

Monday, March 11th 2024, 4:19am

OK - Sorry. I just recalled that some people have had PWM issues with some Artic fans. I don't know why you are seeing lower RPM for the fans when they are plugged into a port on an Aquaero 6XT or D5 Next vs when they are plugged into a PWM port on your motherboard.. Perhaps someone from Aquacomputer will chime in here. Good luck.

sultan.of.swing

Junior Member

Monday, March 11th 2024, 5:50am

Quoted from "Speedy-VI"

OK - Sorry. I just recalled that some people have had PWM issues with some Artic fans. I don't know why you are seeing lower RPM for the fans when they are plugged into a port on an Aquaero 6XT or D5 Next vs when they are plugged into a PWM port on your motherboard.. Perhaps someone from Aquacomputer will chime in here. Good luck.
Yep no worries, This is the reason I am wondering if some sort of filtering/smoothing is happening.

I know usually when you apply smoothing to let's say something like a vehicle dyno graph the more smoothing you apply to the X axis the smoother the curve looks but the lower the numbers will generally be over the X axis.

I wonder if something like that is being applied to the fans.

Honestly it has to be because if you ever have watched a fan on a fan header on something like a motherboard the RPM will fluctuate a bit even if the PWM signal is steady but if you look at the fan graph over time from a fan connected to an aquaero it is perfectly smooth 0 RPM deviations.

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