An LG B4 OLED that flickers, with a picture that pulses in dark scenes, a screen that flashes or a brightness that wobbles, has an effect that is partly normal OLED behavior and partly a setting or cable matter, so the first job is to tell which it is. This is LG's 2024 entry OLED, with the Alpha 8 processor, four HDMI 2.1 ports and a refresh rate up to 120 hertz.
The checks in more detail
On a self-emissive panel, brightness in very dark scenes depends on the refresh rate, and when a game or a source uses variable refresh rate, small changes in frame rate can make dark areas flicker faintly. This is called VRR flicker, and it is seen on many OLEDs and most noticeably in dark, loading and menu scenes. If the flicker is faint and appears in games, turn it down. In the game's settings, cap the frame rate at a steady figure, such as 60 or 120 frames per second, so it does not swing; many games have a frame-rate limit option or a locked mode.
In the TV's settings, turn off VRR for the input in Game Optimizer if the effect annoys you, or reduce the brightness slightly in dark scenes. Some games and consoles have a setting for VRR that you can turn off for the affected game. Make sure the console is set to the right output, such as 4K 120 hertz, and that Auto Low Latency Mode is working. If the flicker is a visible flash or a dropout, suspect the cable or the source. Use a certified ultra high-speed HDMI cable, which supports 48 gigabits per second, and try another HDMI port.
A cable that is not up to it causes flashes at 4K 120 hertz. Reduce the output to 4K 60 hertz to test. Check that the TV's software is current in Settings, Support, Software Update, since LG fixes flicker bugs. A power-saving setting that dims the screen according to the content can also seem like flicker; turn off Energy Saving and the automatic brightness. Try another source. If the screen flashes on every source with a good cable and the latest software, contact LG with the model number.
Differential
Likely causes of “LG B4 OLED TV screen flickers, flashes or goes black intermittently”, and how to tell them apart
- 1
VRR flicker
What separates it A faint pulse in dark scenes in a game
How to confirm Cap the frame rate or turn off VRR for the input
- 2
An unstable frame rate
What separates it Brightness wobbles with the game's frame rate
How to confirm Lock the frame rate in the game
- 3
A cable not up to 4K 120 Hz
What separates it Flashes or dropouts
How to confirm Use a certified ultra high-speed cable
- 4
A power-saving setting
What separates it Brightness shifts with content
How to confirm Turn off Energy Saving and auto brightness
- 5
An old software version
What separates it Flicker bugs
How to confirm Update the TV
Before you touch a setting
Record this first — changing settings destroys the evidence
- When the flicker appears
- Which source and game
- What cable is used
- The software version
Try in this order
0 of 6 completedNote when it happens
ReversibleGames or all sources.
Lock the frame rate
ReversibleIn the game.
Turn off VRR for the input
ReversibleIf needed.
Use a good cable
ReversibleUltra high-speed.
Turn off Energy Saving
ReversibleAnd auto brightness.
Update and contact LG
ReversibleIf it persists.
Model-specific
What is true of this model and not of its siblings
- VRR flicker
- A known effect on OLEDs in dark scenes.
- Frame rate
- A steady rate reduces it.
- Cables
- A certified cable prevents flashes.
- Power saving
- It can dim the screen with the content.
- Software
- Updates fix known bugs.
- LG help
- Quote the model number.
Stop boundary
When this stops being a self-service repair
- !Do not use damaged HDMI cables
- !Do not open the TV
- !Contact LG if the screen flashes on every source
Evidence ledger
Sources behind this answer
Exact questions
Common questions
Why does my OLED flicker in dark scenes?+
VRR changes brightness slightly as the frame rate varies.
Is it a defect?+
Usually not.
Does the B4 do 144 Hz?+
No, 120 Hz.
Can a cable cause it?+
Yes.
Should I turn off VRR?+
If the flicker bothers you.