Question How should I set the best fan curves for my system? (12700KF, Fractal Lumen)

[Mlit]

I'm still a newbie to liquid cooling. Got my system stable after some issues, I do feel like my cooling isn't the best it should be like it should be a few degrees lower than it is. I've been struggling to find examples of how to apply good fan curves for my chassis, AIO fans and the radiator pump itself. I'm aware that things obviously get hotter when crunching the numbers but I have no metrics for how things should be relative to my specifications. I was wonder if anyone could help out here. Currently I'm setting what I assume are acceptable curves on Armoury Crate but havn't even dared to try it in my BIOS instead.

Relevant specs for this subject include:
12700KF
Fractal Lumen S24, default fans at default RPM.
Fractal Meshify 2 Compact, default fans at default RPM.

I've played around with the rad and dropped it from the default 4000 RPM to something around 2600 just to keep it quiet. I do intent to undervolt the CPU at some point to reduce power consumption and run cooler. Can someone recommend what PWM is should be setting for specific temperatures and how to do it in BIOS if that is the better path? It would be very much appreciated.

 

[JohnBonhamsGhost]

there is no set profile that can be used for all systems.
each configuration and each environment are different for each user.
depending on the ambient temperature in the room fan speeds can be different even for the exact same build.
you need to experiment with fan speeds, locations, orientation until you find the best cooling with acceptable noise.

the difference between setting a profile in the BIOS or using motherboard control software is negligible.
it's really a matter of preference which option to use.


i set my current case intake fans at ~40% @ 35°C, ~60% @ 45°C, ~85% @ 60°C.
exhaust at ~50% @ 35°C, ~65% @ 45°C, ~90% @ 60°C.

radiator fans set at 30% @ 30°C, 60% @ 45°C, 90% @ 60°C.

you can see a detailed layout of this current setup in my signature.

 

[Paperdoc]

Most AIO systems including yours are designed with the intent that your PUMP will always run at full speed. You have chosen to reduce your speed to about half the flow rate. The result is that the circulating fluid is hotter than "normal". This means two things: under most conditions, the CPU chip it running at a higher temp than expected so the rad FANS will be running faster that "normal" trying to cool the circulating liquid. And at some point of higher workload those fans will reach their max speed and be unable to do any better cooling.

I am intrigued, though, by your statement "dropped it from the default 4000 RPM to something around 2600 just to keep it quiet.". Most PUMP units are very quiet at full speed; noticeable noise at a pump may indicate it has air bubbles trapped inside and is "cavitating". That condition can produce noise, AND will impede fluid circulation so the AIO system cannot cool as well as it should. ONE way to try to change this is to get your system running at idle, then pick the whole thing up and slowly tilt it around in several directions hoping to get air in the pump up to the "top" of the pump so it can be forced out. You might want to try this as you have it working, and again with the pump speed set to full.

 

[Mlit]

Most AIO systems including yours are designed with the intent that your PUMP will always run at full speed. You have chosen to reduce your speed to about half the flow rate. The result is that the circulating fluid is hotter than "normal". This means two things: under most conditions, the CPU chip it running at a higher temp than expected so the rad FANS will be running faster that "normal" trying to cool the circulating liquid. And at some point of higher workload those fans will reach their max speed and be unable to do any better cooling.

I am intrigued, though, by your statement "dropped it from the default 4000 RPM to something around 2600 just to keep it quiet.". Most PUMP units are very quiet at full speed; noticeable noise at a pump may indicate it has air bubbles trapped inside and is "cavitating". That condition can produce noise, AND will impede fluid circulation so the AIO system cannot cool as well as it should. ONE way to try to change this is to get your system running at idle, then pick the whole thing up and slowly tilt it around in several directions hoping to get air in the pump up to the "top" of the pump so it can be forced out. You might want to try this as you have it working, and again with the pump speed set to full.

I may remount the radiator at the front instead of in the ceiling like I have now then. But I do wonder in that case how I would manage to fit the tubing at the bottom when a graphics card is in the way.

 

[Paperdoc]

Actually, for the particular point of trying NOT to trap air in the PUMP, having the pump BELOW the rad is better in general.

 

[Phaaze88]

I may remount the radiator at the front instead of in the ceiling like I have now then.

Highly recommended that you do, as pump in radiator models will not last long if top mounted; you're exposing the pump to air even as this is posted. There are 3 locations for pumps in AIO/CLCs, and they affect viable mounting positions:
Pump head or cpu block: Mounting radiator at the bottom of a case is no good*. At the front, having the top of the radiator positioned lower than the pump head is also no good.
Pump in radiator: No to top or bottom mounted radiator. Only the front is actually viable - well, the rear is too, but I'd never suggest using a 120mm unit to anyone.
In-line pump: Pretty much the same as pump head.

The reason for the asterisk is that I currently have a radiator mounted at the bottom of the case, but it has a window in the pump head, allowing me to keep track of fluid level, and it's refillable.

But I do wonder in that case how I would manage to fit the tubing at the bottom when a graphics card is in the way.

The 'don't do it like this' has been taken out of context constantly, when the entire point is that it's fine as long as the pump isn't the highest point of the loop.

Even after that, you're still screwed with the triple fan AIO. Over time, when the fluid level gets low enough, you will hear noise around where the barbs meet the radiator. More and more air is pooling there.
You'll be forced to replace the cooler due to how annoying it is, even though the cooler isn't actually broken.
Dual fan AIOs are much easier to flip upside-down(or right-side up?).

 

[Mlit]

I have gone and remounted the radiator to the front panel. I think it actually improves the cooling now. CPU in idle now hangs around 19-23 C though I didn't pay attention to exactly what it was before but it was certainly higher. It's also eliminated two surplus fans which would have cooled the radiator in the ceiling. I've upped the RPM on all the fans a little, too. At the very least I now know I've improved the rad's life span.