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Commander Pro PWM issue - Not smoothly following curve


philtep
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I have two Commander Pros (CPs) driving a total of 14 fans.

 

CP1 has 4 QL120s + 3 Noctua A12x15 (with 3-in-1 splitter), total 5 ports used.

 

CP2 has 5 QL120s + 2 Noctua A12x15 (with 2-to-1 splitter), total 6 ports used.

 

They are both hooked up to a USB hub -> header (due to the CP daisy chaining USB issue with AMD chipsets).

 

I have two curves set up in iCue, and I copied them exactly to both CPs (quadruple-checked). They both "follow" the curve as instructed but CP1 does it very unevenly, while CP2 does it extremely smoothly. See attached graph of RPMs during a 30-min Cinebench run to test temps.

 

What could be causing this? I've graphed the 12/5/3.3v of both CPs to see if there were any drops. They were so perfectly even that it wasn't even worth showing (although I'm logging 15-sec intervals and it could be a millisecond drop - not sure).

Capture.thumb.PNG.b6e7e475984bc736ec8570f42b45fe48.PNG

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CP1 has 4 QL120s + 3 Noctua A12x15 (with 3-in-1 splitter), total 5 ports used.

 

It is most likely the 3 to 1 splitter. The Commander has trouble with this and it is not as simple as works or does not work. In my experience with a dozen different splitters, the performance can be erratic. It may work one day, then not the next. Some never worked. We generally recommend you not use the triples if you can help it.

 

Of course the A12's are the odd number on that controller, but you have 1 free one. If you have a 2 way PWM splitter, try it and move the other off.

 

Other options involve using a powered PWM hub to offload large groups of fans. I end up doing this for cases where the logical pairing is in groups of 3 or more. That would effectively become the 3 way splitter, but powered and using the 1 PWM hub as control. For your set-up, I don't see a benefit of doing this if you already have 2 way PWM splitters or unless there is a prohibitive reason for pairing any 2 of the QLs.

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Thanks. I will test this tonight and report back.

 

Commander Pros are great but they seem to have a lot of quirks and issues.

Would be great to have a thread dedicated to listing quirks and their solutions (like the AMD USB daisy chain issue, this potential 3-way splitter issue, etc)

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I ran some tests. I completely unplugged all three Noctuas from CP 1 to see if PWM would be smooth. It continued to follow the same jump my step-ladder pattern with just 4 QLs attached. I also moved one QL from CP2 over to CP1 and ran test. That new QL also followed the pattern. I’m now convinced there is something very odd going/broken with this Commander Pro.

 

I did reset it with the little button (plug sata in while pressed, then release). ICue erased my curves so I assume the reset work... yet nothing changed.

 

Any other ideas?

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OK, then this is something else. Maybe some type of issue with the PWM wave shape, but the exact cause really doesn't matter. It's not doing its job and this is clearly hardware related. Contact Corsair Support for a replacement or if new, going through the vendor may be faster.
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I am ready for Commander Pro II and those two items are 1 and 2 on my list of things to improve on. What you are experiencing with control is not a common issue. Most people run into a different way while trying to use certain popular European spec PWM fans. The AMD thing is unfortunate, but then it worked on the prior AMD boards. You've been hit twice which is too bad. It really is a useful piece of hardware. I can't imagine having to go back to the BIOS for fan control and if you are on a full water cooled system the temp probes are extremely useful.
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