What Makes a Computer Monitor Flicker?

Monitor flicker can often be extinguished by increasing the monitor's refresh rate — meaning, how often the screen updates every second. The monitor updates its display several times per second based on the information the computer sends it: It actually is always flickering in a sense, but usually this happens so fast that the human eye doesn't notice it. The lower the refresh rate, the more likely a person will be able to perceive screen flicker. Refresh rate is controlled by the operating system. According to PC Magazine, flicker may be more noticeable in a brighter room.

A loose or defective monitor cable can cause monitor flicker by sending an inconsistent, disrupted video feed to the monitor. A loose cable can be reconnected to resolve the problem. If the cable's connection pins are bent, straightening them may reestablish the connection and stop the flicker. If the cable itself is broken, swapping out the cable for a new one will fix the problem. Some computers and monitors have multiple connection ports: try using different ones on either device to diagnose a damaged port. Laptop screens can flicker when the internal motherboard-to-monitor connection is loose or damaged as well.

Any other electronic devices near the monitor may produce a magnetic field that will cause the screen to flicker. You can stop this interference by moving nearby electronic devices like fans and phones away from your computer. Additionally, improper grounding and electrical interference from a power outlet can cause a monitor to flicker. Try connecting the monitor to another power outlet to see if the current outlet is causing the flickering.

Sometimes specific video cards will cause flicker in specific monitors due to programming errors in the drivers, or the software that runs the hardware. Running Windows Update or installing the latest video card drivers from the device manufacturer's website may resolve whatever programming error is causing the disruption. According to PC Magazine, one notable case of bad drivers leading to screen flicker involved a batch if iMacs released in 2010.

Screen flicker can be an indication the monitor or the graphics card is failing. Try using the monitor on a computer with a different graphics card to test it. If this doesn't solve the issue, it may indicate that the monitor itself is failing.You can also likewise test the CPU by testing it with a different monitor; if it continues to flicker in this case, this may indicate that the graphics card needs to be replaced.