With a LNA, some fans won't speed up when the motherboard is supplying low voltage. It should speed up when it's high enough in the fan curve.I just added a Noctua P12 to the side bracket and connected it with the included low noise adapter to my Asus Z270i Strix Gaming but the fan doesn't spin. It just barely moves forward and backwards. Would could I've done wrong?
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Oh well, the P12 seems to be off when not needed and turns on if needed. Does this sound normal to you? I am not familiar with this.
Try turning it up in AI Suite, or the bios if you don't want to mess with that.