Fans & Curves Not Applying

Your curve saves fine, but the fan keeps its own speed.

  1. Check the fan is actually bound to the curve. A curve only drives the fans assigned to it. On the Cooling page, each fan card has a Fan mode selector; set it to your curve (or to Manual for a fixed test speed). Creating a curve does not assign it to anything by itself. See Building a Fan Curve.
  2. Check the fan is controllable at all. Nexus can only drive fans that expose a control channel: motherboard fan headers, GPU fans, and supported USB hubs and coolers. A fan Nexus can read but not control is labeled Fixed speed - not controllable on its card. Which fans qualify is covered in Fan Control Basics.
  3. Close other fan software. Two programs writing speeds to the same controller fight each other, and the loser looks exactly like a curve that does not apply. If Nexus recognizes a running conflicting app it shows a Conflicting apps detected warning where you choose which apps Nexus terminates. See Other RGB & Fan Software.
  4. Test with a fixed speed. Set the fan's Fan mode to Manual and drag the speed up and down. If the RPM reading follows, control works and the issue is in the curve setup (its temperature source, points, or response time). You can also run Calibrate, which cycles duty from 100% to 0% over about 40 seconds and marks fans that do not respond as Disconnected.
  5. Check the controller is still connected. Fans behind a hub or all-in-one cooler follow that controller; if it dropped off USB, there is nothing for the curve to write to. Work through Device Not Detected, and see Cooling Devices for how hub-connected fans are handled.
  6. Restart the service. Windows: restart Nexus Service in Services (services.msc). Linux: sudo systemctl restart nexus. macOS: quit Nexus and launch it again.

If a fan passes the Manual test but ignores the curve, or fails calibration while clearly spinning, collect the logs and report it: Log Files & Reporting a Bug.