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Commander Pro & H115i Fan Curves


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Hello. I've got a question about how to best utilize my fan curves in iCue. I want the fans running as slow (quiet) as possible, while prioritizing hardware health.


I'll quickly cover my C-Pro and H115i setup.


I've got my 2x front panel intake fans and my 1x rear exhaust fan connected to the Commander Pro. I left my 2x top radiator exhaust fans connected to the H115i fan control.


My C-Pro temp sensors are:


  1. Above Radiator
  2. Below CPU / Above GPU
  3. Below GPU fan exhaust
  4. Bottom Case / Power Supply


I have my C-Pro fans using my GPU Temp sensor. I have the H115i using the "H115i Temp" sensor.


I'm wondering how someone more experienced at all of this would create their fan curves.


All of my fans are Noctua NF-A14 with a 1500RPM top speed.


My GTX 1080 Ti gets above 80°C while playing games (max I've seen is 86°C). After testing the card playing Crysis 3, this article says, "the GTX 1080 Ti’s preset thermal throttle point is 84°C". Using FurMark, the same article later says, "The GTX 1080 Ti settles at 84°C here as well – though it did peak at 86°C before reaching equilibrium – showcasing that regardless of the workload, the card always levels out at its thermal throttling point."


It seems fair to say that anything above 86°C should start to worry me. How should I adjust for this in my fan curve?


In this DevBiker video (

), he briefly mentions that he starts at the max speed and works backwards.


Would you set a fan curve point at 86°C for 1500RPM? Or would you get them up to 1500RPM before 86°C to try to cool things down earlier?


1500RPM is a little loud for me, but seeing that temp get into the mid-80s Celsius scares me a little, and I can put up with the sound.


I have all 3x C-Pro fans using the same curve. The rear exhaust is sitting pretty close to the GPU, however. Would it make sense to have that exhaust running harder than the front intakes?


Should I run the top radiator fans off of the GPU temperature instead of the H115i temp? I suppose it wouldn't hurt to have them expelling more hot air, even if the H115i isn't too hot.


I know there isn't a single right answer for any of these questions. I'll do my best to experiment and test different scenarios.


I've tried to research a lot before asking these questions. There's a lot of wisdom hidden in these forum threads, though, so I'm sorry if someone has already answered some of these questions elsewhere.


I'd love to read any threads or articles that you recommend, and I welcome any advice, suggestions, or opinions that you have.

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I'd ramp up before 86C.


And I'd have the case fans tied to temp sensor #2 or #3 (probably). This way the CoPro can run the fan curves with or without the software running.


I'd also go into Afterburner and set the GPU fan curves a bit more aggressively than they usually are. Keeping them spinning, even at low speed, helps a lot. But the fans won't cool of the ambient air blowing through the cooler is warm - hence setting the fans to sensor #2 or #3.


Also, if the radiator is on top as exhaust, it'll pull GPU heat through it. That's going to have a negative impact on your cooler temps. Those 1080Ti's can put off some heat too!! It'd be better for the cooler temps to flip it to intake.


Just my $.02 worth.

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I agree you should set your peak fan level prior to the throttle point. Once you're there, it's too late and you don't want to trip over that temp marker repeatedly.


I think what you need to find out is how much your front intake and rear exhaust fans actually affect GPU temp. The GPU temp as you know it on the inside of the card. Only the GPUs fans are going to make any difference for that. That is most definitely the place to start. A moderate GPU fan curve can prevent you from getting into trouble in the first place.


The case fans play a different role. They are moving warm air out and hopefully bringing cooler air from outside the case in to the replace. You are working case ambient air temperature as the variable. It seems like you have a decent spread of sensor data to look at. +1C air temp = +1C GPU temp (and everything else in the case). However, be careful of any temp sensor very close to the GPU. That will be largely affected by the waste heat coming from the card. It makes it useful to understand how much heat is coming from there, but you can't use the +1=+1 stuff for that. Surface temps on the GPU exterior are probably in the 50-60C range when you are fully loaded. That does not mean you have raised the entire case temp by 20-30C.


All I can suggest is experimentation. Do your case fans really make a temp difference? I would be surprised if it is more than 1-2C, but when you are at the limit, you take whatever 1-2C you can get. GPU temp makes sense for the rear fan. Eventually, you may figure out its behavior and can switch to one of the temp probes. Those work all the time and thus the fans won't blast on boot cycles when the software isn't running. You can do the same thing for the front fans right now by changing their control variable to the sensor above the radiator. Exhaust radiator temp should be equal to coolant temp with a 1-2C offset.

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Thank you both for the great input. I hadn't realized that I could affect the GPU fan curves in Afterburner. I haven't poked around too much in there.




1. Using an ambient temp sensor for the case fans -- I was thinking that the GPU temp would always be higher than the ambient case temp, so by using the GPU temp for my C-Pro fan curves I would have them running more aggressively. As in, the GPU is hot, so therefore I want to increase the ambient air flow to help the GPU cool.


Is that fair? Am I understanding your suggestion correctly?


2. The top radiator fan direction -- I previously had the top fans as intake for the radiator, but then I found this post of yours from 2017 where you say, "For top mount, you should typically be exhaust", so I switched it when installing the Noctua fans.


I think that I see your point, but let me know if I've misunderstood: If I have them as exhaust, they're pulling the GPU hot air through the radiator, which will give the H115i hotter air. Whereas if I have them as intake, they'll give the H115i (and the case) cooler, fresh air.


This will leave my single rear fan as my only case exhaust. Maybe I can rig up another exhaust, or leave that rear fan running a bit more aggressively.




You raise very good points. I'm curious why you would use the GPU temp for the rear exhaust, but not necessarily match it with a similar fresh air intake on the front? Perhaps because I have 2x fans on the front and only 1x fan on the rear?


If I make the radiator fans intakes, then my rear fan will be the only exhaust, which would justify a higher curve for it too, in my mind.


Thanks again, both of you. I really appreciate it.

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@DevBiker -- RE: Using a case sensor vs using GPU temp for my intake. I see your point now. I was overlooking a piece.


I realize that I don't have a sense of what healthy case temperatures are for me. I've only had the CoPro a few days. I think I'll move my sensors away from hardware pieces and monitor case areas. That will address part of c-attack's concern. I had been thinking that having extra data points around pieces of hardware was my goal. But I have other sensors/software for that. I can use these sensors to monitors data that I don't already have access to.

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1) Yes, you are on the right track. But I think, by now, you've gotten that using the temp sensor also gives you control w/o the software. And those temps will increase with GPU temperature.


2) Yes, typically. But it's not hard and fast. Additionally, in the years since then, I've modified this a bit, especially as GPU heat has become a bigger issue. It's a balancing act and sometimes a bit of experimentation is required to get the best results.


Using GPU temp for exhaust ... this pulls the GPU heat out quicker and helps draw cooler air from the front through. This is especially important if the cooler is in exhaust - you'll want to get the GPU heat away from it.

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