Monitor Flickering or Lines on Screen: Causes and Fixes
Tell whether the problem is the cable, the graphics card, or the monitor itself.
1. Rule out the cable first (the most common cause)
Try another cable, and if you have one, another type of connection (HDMI instead of DisplayPort or vice versa) — a faulty or poorly connected cable causes intermittent flickering very frequently.
2. Confirm the configured refresh rate
Display settings → Advanced display settings → confirm the selected refresh rate matches what your monitor supports — a misconfigured one can cause visible flickering.
3. Update the graphics driver
An outdated driver, or one that was just installed with problems, is a common cause of flickering — update it from your graphics card's manufacturer's website.
4. Fixed coloured lines: probably the panel
Important distinction: if it is flickering (intermittent, comes and goes), it is usually cable/settings/driver. If it is fixed coloured lines that don't change or disappear, it points to physical damage to the monitor's own panel — much less fixable through software.
Confirm whether it's the monitor or the graphics card
Connect the monitor to another machine. If the problem persists there too, it's the monitor; if it disappears, the problem is with your graphics card or its connection.
Frequently asked questions
What is the difference between flickering and fixed lines?
Intermittent flickering is usually due to the cable, settings, or driver — fixable. Fixed coloured lines that don't change point to physical panel damage, much less fixable through software.
How do I confirm whether the problem is the monitor or my graphics card?
Connect the monitor to another machine. If the problem persists there too, it's the monitor. If it disappears, the problem is with your graphics card or its connection to the original monitor.