Changing fan speed in iCue does nothing to aio cpu fans

I currently have the Commander pro controlling all my rgb fans and lighting. I can use iCue to change the fan speed at will to Quiet, Balanced, Extreme & Zero RPM. I am able to manually change the case fans to extreme and they will get up to between 1400-1500 RPM. However when I change the AIO fans to Extreme it shows them only going up between 700-730 according to the iCue software but they don't even look to speed up that. CPU temps are around 28c so not sure if the fans simply won't go higher due to the CPU temp but I thought manually changing the fan speed would at least produce some results but not seeing any. I can change the fan speed to Zero RPM and they do in fact stop spinning so I know it is working for at least that part of it.

Any ideas what may be the cause of the fans AIO CPU fans not going faster than 730 when putting them on Extreme?

You need to look at the control variable being used. For the Commander, those 3 presets default to CPU temperature as the only guaranteed data point every system has. However, it makes for a lousy control variable and case fan (or radiator fan) speed won't impact CPU temp directly. You want to get off those presets. Go to the Performance Tab and select + to create a new "cooling mode" or custom curve. Variable choices are in the Sensor drop down menu. Quick and easy choices for you would be GPU temp or H1xxi Temp (whatever cooler model you have). Long term, the temp probes that comes with the Commander are the native source for control, work without the software running, and of course case fans help regulate case internal ambient temperature. It helps to have some value for that.

The cooler will control it's fans from coolant temperature, as it should. Your CPU temp is the result of the voltage being applied to it from the socket, less the heat physically conducted off the CPU. Fan speed or pump speed does not impact that rate of conductivity and everyone is voltage limited, no matter how large their cooling system. In turn, the water system does not do any 'cooling'. It takes the heat from the CPU and transports it elsewhere for disposal. However if you don't get rid of the heat, it will transfer back across the cold plate to the CPU. In effect, coolant temp is the minimum possible CPU temp at 0 volts -- it's your baseline. The relationships is +1C coolant = +1C CPU temp. The fans do not need to speed up when you open a folder, launch a program, or start some level of load. They can't cool the underside of the CPU. It's only when heat is moved into the coolant stream that they become part of the equation. If the coolant temp does not go up, then you are already removing all the heat being dumped in.

For the AIO, you can stick with the presets curves or even better is to create your own (Performance Tab +) and then choose one of the three shape tools in the upper right hand corner. Those correspond to the Quiet, Balanced, Extreme presets, except now you can see the control points and understand what it's doing. It also allows you to make fine adjustments, like to idle speed. If your room temp is 25C, then you certainly can't get coolant or anything else below that. Most people will see idle coolant temps in the +4-7C range above the room temp. There is no point in trying to blast your way through that, but for many in Summer the idle speed will be too high. The default curves were meant for a 20-23C room. I know I can't hold that on a hot afternoon and need to relax the curve a bit.

Thanks for responding c-attack

I guess I didn't explain it right. I understand how the AIO works in that similar to a car's radiator, the fans in front of them will only automatically speed up as the coolant temps get hotter in order to cool down the engine.

What I'm saying is that if I manually change my case fans in iCue, not the AIO fans, to 'Extreme' I can hear them rev up and iCue says they get up to about 1400 rpm. I can see that RPM in iCue and also hear them physically speed up to about that. Then I can change it back to 'Quiet' and they go back down to about 450rpm and they no longer sound loud. However, if I do the same thing to my AIO cooler fans and change those to 'Extreme' they never go above 730rpm and it never even sounds like it is speeding up to that either. Shouldn't they speed up to about 1400 rpm as well and shouldn't I be able to hear them?

"Quiet" for the Commander is the not the same as "Quiet" for the AIO. Different control variable, different scale, different data points. Same thing for the other two presets as well. It's just a generic term.

For the AIO fans, if you are at a low enough coolant temp, all three presets will be more or less the same before separating into clearer differences at higher coolant temperatures. If you create a custom curve + and then use the shape tools in the upper right, you will be able to see the data points and the behavior will make more sense.

For the Commander in default mode, it's running from CPU temp and we have no idea what the data points are. Most people will get a fan blast no matter what because most recent CPUs don't sit flat at 700 Mhz anymore. Near constant activity with chip level power management. The fans are essentially out of control. This is why I suggest you get off those, create a custom curve, and pick something you can see and manage. There is no adjustment to those three presets and no one needs 1400 rpm fan speeds at the desktop.