Diagnosis
You are hearing coil whine from the monitor's internal power supply or circuitry. It is an auditory phenomenon caused by components vibrating at high frequency, not a sign of imminent failure.
How to Fix It
Coil whine often varies with on-screen content and brightness. Lower the monitor's brightness from the OSD. Navigate to Picture > Brightness. Reduce the setting incrementally. The whine often lessens or changes pitch as power draw changes.
If That Didn't Work
The whine can be exacerbated by specific refresh rates. Try changing the refresh rate in Windows display settings from 240Hz to 144Hz or 120Hz. Test if the noise diminishes at a different fixed rate.
Heads Up
This noise is common in high-refresh-rate gaming monitors with powerful internal scalers and power circuits. It does not affect performance or longevity. If the sound is accompanied by a burning smell, excessive heat, or visual artifacts, power off immediately and contact support.