Apple M Processors Might Cause Dell Monitors to Flicker

Summary: This article contains information about issues related to screen flickering on Dell monitors when connected to an Apple system with an M Processor.

This article applies to This article does not apply to This article is not tied to any specific product. Not all product versions are identified in this article.
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Symptoms

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

Cause

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.

Resolution

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.

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.
    1. Go to the Apple menu, followed by System Preferences. Click Displays > Display Settings.
    2. Select the monitor that is connected to your Apple system from the shown list:
      macOS Display Settings, Refresh Rate
      macOS Display Settings, Select 60 Hertz

     
  • Step 2: Turn off Auto Adjust Brightness and True Tone
    1. Go to the Apple menu, followed by System Preferences. Click Displays > Display Settings > Built-in Retina Display.
    2. Uncheck Auto Adjust Brightness and True Tone.
      macOS Display Settings, Auto Brightness and True Tone Options
      Turn off Auto Adjust Brightness and True Tone

     
  • Step 3: Use the Light Appearance
    1. Go to the Apple menu, followed by System Preferences. Click Appearance.
    2. Select the Light Appearance.
      macOS Appearance Settings, Light Setting
      Use the Light Appearance Option

     
  • Step 4: Turn off Night Shift
    1. Go to the Apple menu, followed by System Preferences. Click Displays > click the Night Shift button.
    2. Set the Schedule to Off.
      macOS Display Settings, Night Shift
      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

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Affected Products

Dell C1422H, Dell 24 Video Conferencing Monitor C2422HE, Dell 27 Video Conferencing Monitor C2722DE, Dell 34 Video Conferencing Curved Monitor C3422WE, Dell P2421DC, Dell P2422HE, Dell P2721Q, Dell P2722HE, Dell P3221D, Dell P3222QE, Dell S2422HZ , Dell S2722DZ, Dell S2722QC, Dell U2421E, Dell U2421HE, Dell U2721DE, Dell U2722D, Dell U2722DE, Dell U2722DX, Dell U3421WE, Dell U3821DW, Dell U4021QW, Dell 32 Gaming Monitor G3223D, Dell P1424H, Dell P2423DE, Dell P2424HEB, Dell P2723DE, Dell P2723QE, Dell P2724DEB, Dell P3223DE, Dell P3223QE, Dell P3424WE, Dell P5524QT, Dell P6524QT, Dell P8624QT, Dell S2723HC, Dell S3423DWC, Dell U2424H, Dell U2424HE, Dell U2723QE, Dell U2723QX, Dell U2724D, Dell U2724DE, Dell U3023E, Dell U3223QE, Dell U3223QZ, Dell U3224KB, Dell U3423WE, Dell U3824DW, Dell U4323QE, Dell U4924DW ...
Article Properties
Article Number: 000331897
Article Type: Solution
Last Modified: 17 Jun 2025
Version:  1
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