I built this PC two days ago, and the fans on my Liquid Freezer 3 Pro 360 were stuck around 3000 RPM regardless of the BIOS settings. Updating the BIOS didn't help, but moving the fan cable from CPU_FAN1 to SYS_FAN2 fixed the issue. I configured that header for PWM control, set the temperature source to the CPU, and created a fan curve. Is it safe to leave the AIO fan cable connected to SYS_FAN2 on my MSI MAG B860 Tomahawk WiFi motherboard, or should it be connected to CPU_FAN1?
2 Answers
That’s fine. The fan headers can generally control the fans in the same way, so if SYS_FAN2 is responding properly to PWM mode and your CPU-based curve, you can leave it there. Just make sure the BIOS isn’t set to stop monitoring CPU_FAN1 or treat it as a missing fan, since some boards show a warning when that header is empty.
You can also fine-tune the curves for a quieter system. Keep the pump at a steady speed or let it ramp up fairly quickly, while allowing the radiator fans to increase more gradually. If your setup exposes the coolant temperature, using that for the fan curve is usually smoother than reacting directly to quick CPU-temperature spikes. The VRM fan, if your board lets you control it separately, should follow VRM temperature.
In my experience, changing the pump speed constantly doesn’t help much. A fixed speed that’s quiet is usually enough, then the radiator fans can follow the coolant temperature when that sensor is available.
Thanks! This is my first build, so I wasn’t sure whether using SYS_FAN2 for the radiator fans was considered incorrect.