Loading...
Loading...
Video flicker on external Dell monitors might appear after a while when an Apple M Processor system is connected. The flicker may even remain when the system is disconnected and reconnected. Affected Monitors: Dell C Series Monitors Dell G Series Monitors Dell P Series Monitors Dell S Series Monitors Dell U Series Monitors C1422H C2422HE C2722DE C3422WE G3223D P2421DC P2721Q P3221D P2422HE P2722HE P3222QE P2423DE P2723DE P2723QE P3223DE P3223QE P1424H P2424HEB P2724DEB P3424WE P5524QT P6524QT P8624QT S2422HZ S2722DZ S2722QC S2723HC S3423DWC U2421E U2421HE U2721DE U3421WE U3821DW U4021QW U2722D U2722DE U2722DX U2723QE U2723QX U3023E U3223QE U3223QZ U3423WE U4323QE U2424H U2424HE U2724D U2724DE U3224KB U3824DW U4924DW
The flicker is caused by the monitors LCD panel’s Image Compensation Algorithm (ICA) function repeatedly turning On and Off. The YCbCr Video generated from the Apple system is at 17Gray level, it fluctuates between 15Gary and 17Gary. Hence it is repeatedly turning On and Off, the ICA which has a threshold setting of 16Gray.
Dell Monitor Video Flicker with Apple M Processors This is a known compatibility issue between older Dell monitors and Apple M Processor systems. Before proceeding with the workaround, ensure that the following has been done: Make sure you have the latest version of macOS available for the system and have the latest updates. Test if the issue persists after a system restart. The Thunderbolt port and cable connector are checked for any signs of damage. A different Thunderbolt or USB-C cable has been tested. If the aforementioned steps did not resolve the flickering issue, go to the workaround. If the monitor's LCD panel is flickering, use the monitors LCD conditioning after prolonged flicker. See the LCD conditioning guide in the monitors user guide before implementing the solution. Dell Support Manuals Dell Community: LCD Conditioning Explained macOS Workaround The following four steps should be used to help fix the video flickering: Step 1: Change the Refresh Rate (If applicable) Change the refresh rate to constant 60 Hz or 30 Hz if your monitor supports multiple refresh rates. Go to the Apple menu, followed by System Preferences . Click Displays > Display Settings . Select the monitor that is connected to your Apple system from the shown list: macOS Display Settings, Select 60 Hertz Step 2: Turn off Auto Adjust Brightness and True Tone Go to the Apple menu, followed by System Preferences . Click Displays > Display Settings > Built-in Retina Display . Uncheck Auto Adjust Brightness and True Tone . Turn off Auto Adjust Brightness and True Tone Step 3: Use the Light Appearance Go to the Apple menu, followed by System Preferences . Click Appearance . Select the Light Appearance . Use the Light Appearance Option Step 4: Turn off Night Shift Go to the Apple menu, followed by System Preferences . Click Displays > click the Night Shift button. Set the Schedule to Off . Turn off Night Shift If the workaround is applied and the flicker reappears, disconnect the monitor from the system, and wait at least two hours. Note: These workarounds only mitigate the flicker, this issue is related to Apple M Processors with various monitor brands. Dell has taken steps to reduce flicker in their monitors, but these measures only lessen the impact. If you have any additional questions, contact Dell Technical Support Back to Top
Click on a version to see all relevant bugs
Dell Integration
Learn more about where this data comes from
BugZero Plan
Streamline upgrades with automated vendor bug scrubs
BugZero Prevent
Wish you caught this bug sooner? Get proactive today.