Refresh rate is not frame rate or response time
Refresh rate is how often the display updates each second. A 60 Hz interval is about 16.7 milliseconds, 120 Hz about 8.3 milliseconds and 144 Hz about 6.9 milliseconds. Game FPS is how often the application produces a new frame; pixel response time describes how quickly panel pixels change state.
A faster refresh mode can reduce the wait for the next scan and make motion look smoother, but it does not guarantee high game FPS or eliminate slow pixel transitions. Those parts must be evaluated separately.
Measure the display the browser is actually using
Move the browser window entirely onto the target monitor and start the refresh-rate test. Keep the tab visible and avoid moving the window during sampling. The page estimates Hz from animation-frame intervals, so a busy system or hidden tab can disturb the result.
A stable estimate within a small margin of the configured mode is normal. Fractional video timings and sampling mean 143, 144 and 145 can all describe a 144 Hz setup more plausibly than a reading fixed near 60.
- Place the complete browser window on the display being checked.
- Close heavy graphics work and run the measurement three times.
- Compare the stable cluster with the active operating-system display mode.
If a fast monitor remains near 60 Hz
Open the operating-system advanced display settings and choose the intended rate. New monitors often default to 60 Hz. If the higher choice is missing, confirm that the cable, port, dock and adapter support the desired resolution and rate together; bandwidth support at a lower resolution does not guarantee the same rate at 4K.
Duplicate or mirror mode may synchronize displays to a shared rate. Try extended desktop. On a laptop, connect power and disable battery-saving or dynamic-refresh features temporarily. Vendor graphics software may also have a per-display mode or custom-resolution setting.
Variable refresh and multiple monitors complicate timing
Adaptive-sync systems vary presentation to match rendered frames, so timing may not stay on one exact interval. Desktop browsers also schedule compositing across displays with different rates in ways that vary by operating system and browser version.
If the result follows the wrong display, stop spanning the window, reload after moving it and compare with the secondary display temporarily disconnected. This isolates scheduling behavior without claiming that either monitor is defective.
What the browser test does not measure
Animation timing cannot certify panel overdrive, input lag, scan-out behavior, motion blur or pixel response. It also cannot ensure that a game will render at the same rate. Controlled camera or instrument testing is needed for several of those properties.
Use the web result to confirm configuration and spot a large mismatch. For purchasing comparisons, consult measurements that state their equipment, mode, resolution and overdrive settings rather than combining every display property under a single speed label.