A flickering monitor is irritating from the first minute: the picture jitters, goes black for a fraction of a second, horizontal lines run across the screen or the brightness seems to "breathe". After an hour in front of it, your eyes and head ache. But flicker isn't just about comfort. It almost always points to a specific fault, and the way the screen flickers often tells a technician straight away where to look.
Types of flicker
| What you see | Likely cause |
|---|---|
| The screen goes black for 1–2 seconds and comes back | Cable or connector, graphics driver, failing graphics card |
| Jitter or "ripple" across the whole screen | Unsuitable refresh rate, damaged cable, interference |
| Horizontal lines rolling across the screen | Poor contact, electrical interference, faulty panel |
| Brightness blinks or pulses | Monitor backlight, monitor power supply, power-saving mode |
| Flicker only in games or video | Driver, adaptive sync, graphics card overheating |
| Only one program or the browser flickers | Hardware acceleration, driver conflict |
Cables and connectors
The most common and simplest cause. HDMI and DisplayPort cables carry an enormous data stream, and any damage — a sharp bend, a crushed conductor, a loose connector — leads to signal loss. Cheap and overly long cables often can't cope with high resolutions and refresh rates: at 4K or 144 Hz such a cable causes dropouts even though it worked fine at Full HD. Adapters such as HDMI-to-VGA or DisplayPort-to-HDMI are another frequent source of trouble.
Refresh rate and settings
If Windows is set to a refresh rate the monitor can't handle reliably, or adaptive sync (FreeSync, G-Sync) is enabled with incompatible settings, the screen may flicker, particularly as frame rates change in games. Sometimes a Windows or driver update resets the settings to unsuitable values.
The graphics driver
A damaged, outdated or — conversely — brand-new but buggy driver can cause brief screen blackouts. A tell-tale sign is the screen going black followed by a notification that the display driver stopped responding and has recovered. If that keeps happening, it's worth investigating: sometimes it isn't the driver at all but the early stage of a graphics card fault.
The graphics card
Overheating, degradation of the chip or video memory, and power problems can all show up as flicker, artefacts (coloured dots, squares, lines) and loss of picture. It's especially worrying if the problems start under load and get worse as the card warms up. A failing graphics card may eventually stop producing a picture altogether.
If coloured artefacts, dots or a "broken-up" picture appear alongside the flicker, especially in games, don't put off a diagnosis. That's often how a graphics card failure begins, and continuing to use it under load speeds the process up.
The monitor itself
A modern monitor's backlight runs from its own power supply and driver circuit. As the capacitors in the monitor's power supply age, the brightness starts to blink, the monitor may not switch on first time or may go dark after a few minutes. A fault in the panel or its ribbon cable shows up as lines and jitter that change if you press lightly on the monitor's frame. Many budget monitors control brightness with PWM — rapidly pulsing the backlight; you can't see it, but sensitive people find it tiring.
Electrical interference
Poor earthing, powerful appliances running nearby, extension leads with many devices plugged in, unstable mains voltage — all of these can cause interference, especially for older monitors connected via analogue cables. In older Tbilisi buildings with worn wiring this is a fairly common problem.
Why flicker is harmful
- eye strain, dryness and headaches during long sessions;
- reduced concentration and productivity;
- the risk that a graphics card or monitor fault progresses to complete failure;
- with power problems, a risk of damage to other components.
What a technician does
- Connects the monitor to a known-good source and the computer to a known-good monitor to isolate the fault.
- Checks cables and connectors and, if needed, supplies a quality cable of the right standard.
- Sets the correct refresh rate, resolution and sync options.
- Reinstalls the graphics driver after completely removing the old one.
- Tests the graphics card under load and checks its temperature and power delivery.
- Diagnoses the monitor and, if its power supply or backlight is faulty, suggests repair or replacement.
How quickly can it be fixed?
When the cause is a cable, settings or a driver, the problem is usually solved within an hour on site. A failing graphics card or monitor power supply takes longer, but at least you'll know exactly what's wrong and what the repair or replacement options cost before spending anything.
Laptops are a special case: flicker is often caused by the display ribbon cable that runs through the lid hinges and gradually wears from opening and closing. The tell-tale sign is the picture breaking up at a particular screen angle.
Call a technician
We'll come to any district of Tbilisi, find the cause of the flicker and fix it — often on the spot. Learn more on our computer diagnostics, driver installation and computer repair pages.
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