Monitor Flickering

Monitor flickering shows up as a picture that blinks, dims for a moment, goes black and comes back, or rolls with faint lines. Screen flickering on a laptop has the same causes. Most of the time it is a loose or underrated cable, the wrong refresh rate or a graphics driver problem, and the quickest fix is to reseat both ends of the cable, then press Windows + Ctrl + Shift + B to restart the graphics driver. After each fix, run the refresh rate test. It shows the rate your screen really runs at and marks dropped frames, so you can see whether the flicker has gone or only moved.

Quick checks

• Run Microsoft's Task Manager test. Press Ctrl + Shift + Esc. If Task Manager flickers with the rest of the screen, the cause is the display driver, the cable or the monitor. If Task Manager stays steady while the rest flickers, an app is causing it: update or uninstall the app you installed most recently.
• Reseat the cable at both ends, and try another port on the computer.
• Reset the graphics driver with Windows + Ctrl + Shift + B. The screen goes black for a second and comes back.
• Turn the brightness to maximum for a moment. Flicker that disappears at full brightness and returns when you dim the screen is backlight dimming, covered further down, not a fault.
• Restart the computer. A real restart, not sleep.

Monitor flickering on and off: check the cable and port

A screen that goes black for a second and returns, or flickers more at higher refresh rates, is losing its signal. A cable too slow for the mode you set is a frequent cause on new high refresh rate monitors.

1. Use a cable rated for the mode you run. 4K at 60 Hz over HDMI needs a Premium High Speed cable. 4K at 120 or 144 Hz over HDMI needs an Ultra High Speed HDMI cable, certified for 48 Gbps and labelled on the box. For DisplayPort, the cable that came with the monitor is the safest choice.
2. Remove adapters, docks and extension cables. Intel's own advice for flicker is to test with a direct connection and no dongles. If the flicker stops, the adapter or dock was the problem.
3. Use the graphics card's ports on a desktop, not the motherboard's, when the computer has a separate graphics card.
4. Check the monitor's power cable and try a different wall socket. A loose power lead makes the whole screen blink, menu included.

If the screen goes black and stays black, the problem has become a lost signal: see monitor no signal.

Set the right refresh rate and resolution

A refresh rate the cable or monitor cannot hold makes the picture flicker or drop out, and two monitors at different rates can make each other stutter.

Windows 11:

1. Open Settings, System, Display, select the flickering monitor, then Advanced display.
2. Next to Choose a refresh rate, pick the monitor's native rate. Rates marked with an asterisk do not work at your current resolution.
3. If you have a Dynamic refresh rate switch, turn it off to test. Windows only offers it on screens that support variable refresh and run at 120 Hz or more.

Windows 10: open Settings, System, Display, Advanced display settings, choose the display and pick the rate under Refresh rate.

Mac: open System Settings, Displays, select the display and choose a fixed rate under Refresh rate. On a MacBook Pro with ProMotion, pick 60 Hz to test whether the variable rate is involved.

Keep each monitor at its native resolution. Then open the refresh rate tester on each screen: a steady reading at the rate you chose and few dropped frames mean the link is stable. If a second screen drops out of Display settings altogether instead of flickering, follow second monitor not detected windows 11.

Update, roll back or reinstall the graphics driver

If the flicker started after a Windows or driver update, roll back first:

1. Search the taskbar for Device Manager and open it.
2. Expand Display adapters, right-click the graphics adapter and select Properties.
3. On the Driver tab, select Roll Back Driver, then restart.

If there is nothing to roll back, install the newest driver: the NVIDIA app for GeForce cards, AMD Software: Adrenalin Edition for Radeon, and for Intel graphics in a laptop, the laptop maker's driver first, then Intel's. For a clean install, select Uninstall device in Device Manager, tick Attempt to remove the driver for this device, restart and install the driver again.

Flickering in games: G-Sync and FreeSync

Monitor flickering while gaming, especially on loading screens, in menus or in dark scenes, is usually variable refresh rate at work. With G-Sync or FreeSync on, the screen's refresh rate follows the frame rate, and when the frame rate jumps around, brightness shifts slightly with it. OLED and VA panels show this the most.

• Cap the frame rate a few frames below the monitor's maximum, in the game or in the graphics driver.
• Turn variable refresh off for that game to compare: Set up G-SYNC in the NVIDIA Control Panel, or the AMD FreeSync switch in AMD Software.
• Some OLED monitors have an anti-flicker or VRR control option in their own menu.
• Undo any refresh rate overclock you set in the monitor menu or driver.

Flicker is not the same as tearing, where the picture splits into offset strips during fast motion. The screen tearing test shows the difference, and the ufo test shows how smooth motion looks at your current rate.

Laptop screen flickering

• Panel Self Refresh. Laptops with Intel graphics save power by letting the screen refresh itself from memory, which flickers on some panels. In Intel Graphics Command Center, open System, then Power, and turn off Panel Self Refresh.
• Brightness based on content. Windows 11 can change brightness with what is on screen, which looks like flicker when you scroll between dark and light pages. Open Settings, System, Display, Brightness and set Change brightness based on content to Off.
• The laptop maker's driver. Intel recommends the laptop maker's graphics driver first on laptops, since it is tuned for that panel.
• The hinge. Flicker that changes when you move the lid is a worn display cable inside the hinge. That is a repair.

When an external monitor flickers only when it is connected to a laptop, connect the laptop's charger, try HDMI instead of USB-C or the reverse, and update the dock's firmware if you use one.

Brightness flicker from PWM dimming

Many screens dim the backlight by switching it on and off hundreds or thousands of times a second, called pulse width modulation. Most people never notice, but some see flicker or get eye strain at low brightness. Raise the screen brightness and lower the room lighting instead of dimming the screen hard. A phone camera pointed at the screen often shows dark bands rolling across a PWM-dimmed display. If you are sensitive to it, look for monitors sold as flicker-free.

When it is a hardware fault

Suspect the monitor when the flicker or lines also appear on its own on-screen menu, on a second computer, or on the BIOS screen before Windows starts. Run the full monitor test and look for lines that stay in the same place across patterns: they point to the panel or its controller. Flicker with a buzzing sound, or a screen that turns itself off and on, points to a failing power supply inside the monitor. Many monitors also have a built-in self test, run with the video cable unplugged, which separates a monitor fault from a computer fault.

For a claim, film the flicker with your phone and note the cable, port and refresh rate you used. Within the warranty, a monitor with a failing backlight or power supply is normally repaired or replaced. Out of warranty, a monitor power board repair can be worth a quote, but a new panel usually costs close to a new monitor.

Flickering questions