How to inspect a screen after changing refresh rate

You changed your monitor’s refresh rate, but now you are not sure the new setting took effect. Maybe the screen flickers, goes black for a moment, or looks no different during scrolling.

Check the display’s reported mode and look for visible problems before settling on a setting. TooLab’s Screens shows details for connected displays, and Display Test checks refresh rate and screen appearance in your browser.

Check the screen after changing its refresh rate

1. Open Screens and identify the display you changed. Note its reported resolution and scale, especially if you have more than one screen.
2. Open Display Test and check the refresh-rate result. Compare it with the rate selected in your computer’s display settings.
3. Look at the screen during ordinary use. Scroll a page, move a window, and watch for flicker, brief blackouts, horizontal lines, or other new artifacts.
4. Use the color test in Screens to inspect the display across different colors. If the problem happens only on one monitor, keep the test on that screen and check its cable and settings separately.

If you did not write down the previous setting, that is okay. You can select a lower, known-compatible rate and repeat the check. A stable picture is more useful than a high number that causes interruptions.

What the result means

The test result agrees with the setting you selected

The browser can observe the screen updating at about the selected rate. That is a useful check that the new mode is active, but it does not prove that every part of the display chain supports every advertised mode. The cable, adapter, dock, resolution, graphics hardware, and monitor can all affect which combinations work. For a quick explanation of rate readings, see how to check whether your screen runs at 60 or 144 Hz.

The result is lower than the selected rate

The selected value may not be active, or the browser may not be able to measure it consistently. Check that you changed the setting for the correct display, then compare the computer’s display settings with the monitor’s on-screen information if it has an on-screen display. Repeat the test after closing demanding apps and animations.

You see flicker, blackouts, or colored lines

The new mode may be unstable with the current resolution or connection. Switch back to the last setting that worked. If the symptoms continue at a lower rate, inspect the cable, adapter, port, and monitor rather than assuming the refresh-rate setting is the only cause.

The picture is stable, but motion still looks blurry

Refresh rate is only one part of motion clarity. Pixel response time, motion processing, and a game’s frame rate can also affect what you see. If you see trails behind moving text, check for monitor text trails as a separate issue.

How to fix it

1. Return to a stable refresh rate. On Windows 11, open Settings › System › Display › Advanced display, select the affected display, and choose a rate that works reliably. On macOS, open System Settings › Displays and select a supported rate when the option is available. If the screen is hard to use, wait for the operating system to revert an unconfirmed change, or connect another display to change it back.
2. Use a supported resolution and rate. In Windows 11, check the resolution and refresh rate under Settings › System › Display › Advanced display. On macOS, review the available options under System Settings › Displays. A lower resolution may allow a higher refresh rate, but use the monitor’s recommended resolution first unless you have a reason to change it.
3. Reconnect the display directly. Turn off the monitor, reseat both ends of the video cable, and test without a dock or adapter if possible. Try another port or a cable specified for the resolution and rate you want. A cable that works at a lower rate may not handle a higher-bandwidth mode reliably.
4. Temporarily turn off variable refresh features. If flicker occurs only while gaming or when the picture changes, disable adaptive sync or variable refresh rate in the monitor’s on-screen menu or graphics settings, then test again. Turn it back on after you have identified whether it is involved.
5. Restart and check for updates. Restart the computer and monitor. On Windows 11, check Settings › Windows Update for available updates. On macOS, check System Settings › General › Software Update. A graphics driver or system update can resolve display-mode problems.
6. Reset the monitor’s display settings. If the computer reports a stable mode but the monitor still flickers, use the monitor’s own menu to restore picture settings or disable an overclocked refresh-rate mode. Check the monitor manual if you are unsure which setting controls this.

When the screen or connection may be faulty

If flicker, lines, or brief blackouts remain at a low supported rate, test another cable and another video source. If the fault follows the monitor across different cables and devices, the monitor may need service. If it happens only through one dock, adapter, or port, that connection is the more likely cause. Keep the monitor’s model, the selected resolution and rate, and a photo or video of the symptom for support or a warranty claim.

Refresh rate is not the same as response time

Refresh rate, measured in hertz (Hz), is how often the display can update its image each second. Response time describes how quickly a pixel changes from one color to another. A higher refresh rate can make movement look smoother, but it does not automatically remove pixel trails or make every application produce more frames. Browser tests are a practical check, not a full monitor calibration or hardware diagnosis.