How to Check a New Monitor Before the Return Window Closes

Why the first day matters more than it should

Almost every manufacturer has a dead pixel policy, and almost none of them will replace a monitor for one dead pixel. The common threshold is three to five bright or dark sub-pixels before a panel counts as defective — and that policy is the manufacturer's, running from the date of manufacture. Your retailer's return window is separate, usually shorter, and usually far more generous. It is the one you actually want to use.

So the useful order is: find any fault while you can still simply send it back, not after you are arguing about a specification.

Dead pixels and stuck pixels — different faults

Run Dead Pixel Test and step through the solid colours full screen. Look closely; a single sub-pixel is small.

A dead pixel stays black on every colour — its transistor has failed and nothing will bring it back. A stuck pixel shows one colour permanently, usually red, green or blue, and is a sub-pixel jammed on. Stuck pixels sometimes recover: cycling colours rapidly for twenty minutes genuinely works occasionally, which is why the tool includes that mode. It is worth trying before starting a return.

Check on black, white and each primary. A pixel stuck on green is invisible against a green field and obvious against black, so a single background proves nothing.

Backlight bleed versus IPS glow — the distinction that decides the return

This is the one to get right, because the two look similar in a dark room and only one is a defect.

Backlight bleed is light escaping around the edges of the panel, usually in patches or streaks at the corners. It does not change when you move your head. It is a manufacturing fault — the panel is not seated evenly — and it is grounds for a return when it is bad enough to see in normal use.

IPS glow is a silvery haze in the corners that changes as you move. Lean left and the right corner glows more. It is inherent to how IPS panels pass light at an angle, every IPS panel has it, and no replacement will be free of it. Returning a monitor for IPS glow gets you another monitor with IPS glow.

Test with Backlight Bleed Test in a properly dark room, on full black, after letting the monitor warm up for twenty minutes — panels look worse cold. Then move your head. If the patch moves with you, it is glow. If it stays exactly where it is, it is bleed.

Refresh rate and variable sync — check they are actually on

A 144 Hz monitor plugged in with the wrong cable, or left on its default setting, runs at 60 Hz and looks it. This catches people constantly, and the monitor is not at fault.

Confirm the rate the display is really receiving with Refresh Rate Test, not what the box says. If it is lower than expected, work through the chain: the cable standard, the port you used, and the refresh rate setting in the operating system, which does not change itself when you plug in a better monitor.

The cable is the most common culprit and the least obvious. The display bandwidth calculator works out whether your combination of resolution, refresh rate and colour depth actually fits down the cable you are using — including what DSC and chroma subsampling change. That is usually the answer to "why will my monitor not do 144 Hz".

Then check variable refresh rate with Adaptive Sync (G-Sync / FreeSync) Test. G-Sync and FreeSync have to be enabled in the graphics driver as well as the monitor's own menu, and having one without the other is the normal state of a new setup.

Response, overdrive and the trails behind moving objects

Run Monitor Ghosting Test and watch the trailing edge of the moving blocks.

A faint smear behind a moving object is normal pixel response. A bright trail in front of or behind it — inverse ghosting, sometimes called overshoot — means the overdrive setting is too aggressive. That is a menu setting, not a fault: monitors ship with overdrive labelled Normal, Fast, Extreme or similar, and the highest setting is very often worse than the middle one. Step it down until the bright trail disappears.

Also run Screen Tearing Test with variable sync off and then on. If tearing does not change, adaptive sync is not actually working, which takes you back to the previous section.

Colour depth and banding

Finally, run Colour Banding Test. A smooth gradient should look smooth. Visible steps mean either a genuinely 6-bit panel using dithering, or an 8-bit panel being fed a signal the cable cannot carry at full depth.

That second cause connects back to bandwidth: at the limit, a monitor will silently drop to 8-bit or to chroma subsampling rather than refuse the mode. It keeps working and looks slightly worse, and nothing tells you. If banding appeared when you turned the refresh rate up, that trade is what happened.

The half-hour checklist

1. Let it warm up twenty minutes — panels look worse cold and you want a fair reading.
2. Solid colours full screen, close up: dead and stuck pixels. Count them against the manufacturer's policy.
3. Dark room, full black: bleed or glow? Move your head to tell them apart.
4. Confirm the refresh rate the display is actually receiving, then check the cable can carry it.
5. Enable variable sync in both the driver and the monitor menu, then verify with a tearing test.
6. Ghosting test, and step overdrive down if you see bright trails.
7. Gradient test for banding.
8. Anything genuinely wrong: start the return with the retailer, not the manufacturer.