Start by setting up your display
144Hz support on the box does not mean that this mode is currently selected. Open the display settings in the system and look at the frequency for the desired monitor. If there are multiple screens, make sure that the one with the test window is selected.
Close heavy tabs and temporarily turn off power saving if appropriate. Keep the window visible and do not drag it between screens while measuring.
Browser frame rate test
FreeLoading the check...
What does the page measure?
The test collects intervals of requestAnimationFrame calls and converts the median interval to frequency. This is watching frames of a browser tab. It includes the influence of browser, system, and device mode, and is therefore not the same as directly measuring updates to the physical fabric.
If the tab is hidden, the series is cancelled. It would be incorrect to continue comparing frames of the background window with the active screen. For comparable results, repeat the measurement under the same conditions and look at several series.
If the system also shows 60 Hz
Check the available modes for your set resolution. The cable, adapter, video card port and monitor input can support different combinations of resolution and frequency. Check the documentation of your specific devices: the name of the interface without version and mode does not describe all the restrictions.
After changing the mode, repeat the test. If the required frequency is not in the list, check the driver and the selected monitor input. Don't install random "boosters" or add unsupported modes just for the sake of a number on a page.
If the system shows 144 Hz, and the test is about 60
Repeat in another modern browser, then with one active screen if that's convenient. Look at your browser's energy saving and hardware acceleration settings. Change one condition at a time and return it if there is no improvement.
A heavy load can cause frame skips. In this case, the median can remain close to the usual interval if gaps are rare. This short test is not a substitute for a lengthy analysis of the game's fluidity and its own frame time graph.
What the result doesn't show
It does not measure pixel response time, delay before the image appears, or the quality of matrix overclocking. For visual inspection use gradients and plain fields. These checks have a different purpose; a good number of hertz does not guarantee the absence of image defects.