Swag Posted March 14, 2019 Share Posted March 14, 2019 Hi, Replaced the ML120s on my H150i with some Noctua nf-a12x25. Problem is, I noticed the middle fan's speed is ~300 RPM higher compared to fan 1 and 2. This happens on both Balanced and Extreme performance settings in iCUE, but weirdly enough all three fans match in RPM on Quiet settings. Any ideas why this is happening? Screenshot of fan RPMs Link to comment Share on other sites More sharing options...
c-attack Posted March 14, 2019 Share Posted March 14, 2019 Swap fan 2 with either 1 or 3 and see if the speed differential travels with the fan or stays on fan channel #2. Link to comment Share on other sites More sharing options...
Swag Posted March 14, 2019 Author Share Posted March 14, 2019 Swap fan 2 with either 1 or 3 and see if the speed differential travels with the fan or stays on fan channel #2. I just did, it seems like it stays with the fan. https://imgur.com/VEsAdxn Does that mean its a problem with that particular fan, or is it the only one that is working as intended? Because the other two doesn't seem to be reaching anything higher than 1.6k RPM on balanced/extreme. Link to comment Share on other sites More sharing options...
c-attack Posted March 14, 2019 Share Posted March 14, 2019 Quiet/Balanced/Extreme are just presets with definite temp = xxx fan speed (%). Create a custom curve to open up the fixed % option. See if it evens out. Assuming this is the NF-A12 PWM version (12v), real max against a radiator should be approximately 1900 rpm. Also, make sure you apply the curve to all three fans (they will highlight yellow). This comes up frequently and I occasionally miss it myself. Link to comment Share on other sites More sharing options...
Swag Posted March 14, 2019 Author Share Posted March 14, 2019 It seems like the problem is still there. I set a custom curve with fixed RPM maxed out for testing, and the only one going to ~1900 RPM is that one fan. The other two remains at ~1600 RPM. Link to comment Share on other sites More sharing options...
c-attack Posted March 14, 2019 Share Posted March 14, 2019 I suppose the next step is temporarily move them to the motherboard or a different fan controller. You can probably get away with moving just one of the 1600 rpm troublemakers. We probably need to establish if it is the fan (same condition with all controllers) or the Commander Pro. We have seen some wonky behavior with the 3000 rpm industrial noctua series, but my NF-F12 2000 Industrial PWM work just fine on the Commander Pro, so I am not sure what we are looking at here. Link to comment Share on other sites More sharing options...
Swag Posted March 14, 2019 Author Share Posted March 14, 2019 Problem solved. It just occurred to me to check the cables as I had a hunch, and turns out I was right. I accidentally used the low-noise adapter that came as accessories of the Noctua fans for the cabling of the two fans. These cables intentionally limits the RPM from 2000 to 1700. Thanks for helping me troubleshoot, c-attack! Link to comment Share on other sites More sharing options...
c-attack Posted March 14, 2019 Share Posted March 14, 2019 I am somewhat relieved. We don't need any more fans on the uncooperative list. Yeah, the Noctua LNAs look just like a regular cable. I didn't realize that model came with a LNA and I would not have guessed they would make it for 1700 rpm. That isn't exactly quiet. Would have figured 1200-1300 to a more appropriate target, but I am not sure why someone would even use it on a PWM fan with a 450-2000 range. Nevertheless, glad it is resolved. Link to comment Share on other sites More sharing options...
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