Response Time Claims and Overdrive

The small number on the box and the pale trail behind moving objects are the same feature. That "1 ms" is achieved by overdrive — pushing each pixel with more voltage than its target colour needs so it gets there faster — and overdrive pushed too hard makes the pixel overshoot, which is what produces the bright halo running ahead of anything that moves.

So the specification is not lying, and it is also not describing what you will see. The useful action is free: find the overdrive setting your panel actually prefers, which is usually not the one that produced the number.

A note on this guide: this rests on how these panels and their overdrive circuits work, and on how the figures are measured, rather than on displays measured here. See how we test.

The problem, as it appears

Two versions, and people rarely realise they are the same subject.

The first: a monitor advertising an extremely low response time still looks smeared in fast motion, and you conclude the specification was marketing.

The second: a monitor that looks fine in most things shows a strange pale edge — an outline that seems to run ahead of a moving object rather than trailing behind it — and nothing in the menu is obviously called that.

Why the specification disappoints

Because of how the number is produced, not because it is invented.

A grey-to-grey figure is measured on the fastest transition the panel can manage, with overdrive at its most aggressive setting, using a measurement window that ignores the slow tail of the transition. Every one of those choices is defensible in isolation and together they select for the smallest possible number.

What you actually see is different in three ways. You see all transitions, not the best one. You probably do not run the most aggressive overdrive, because it looks bad. And your eye notices the tail that the measurement window excluded.

The result is a figure that is real, reproducible, and close to useless for comparing two monitors — which is why a panel quoting a larger number can look cleaner in motion than one quoting a smaller one.

What actually matters

Ghosting and overshoot are opposite faults

The distinction that makes the rest of this legible, and once seen it cannot be unseen.

Ghosting is a dark smear that lags behind a moving object. The pixel is too slow — it has not finished changing before the next frame arrives. Too little overdrive.

Overshoot, also called inverse ghosting, is a pale or inverted halo that runs ahead of the object. The pixel went past its target before settling. Too much overdrive.

They are the two ends of one adjustment, which is why chasing one produces the other.

The middle setting is usually right

Most monitors ship three or four overdrive levels with names that tell you nothing — Off, Normal, Fast, Extreme, or a numbered scale.

The top setting generally exists to hit the specification. It is the one measured for the box and it is frequently the one that produces obvious overshoot in real use.

The middle setting is the usual best answer, and there is no way to know without looking, because the tuning differs per panel and per unit generation.

It changes with refresh rate, which matters if you use VRR

The detail that catches people, and it is worth understanding before buying.

Overdrive tuning that looks clean at the panel's maximum refresh rate can overshoot badly at lower rates, because the pixel has longer to settle and the same boost is now too much.

That is a direct problem for variable refresh rate, where the rate moves continuously with the frame rate. A monitor with variable overdrive adjusts its tuning as the rate changes. One without is tuned for a single rate and compromised everywhere else — so a display that reviews well at its maximum can look poor at the rates a demanding game actually runs at.

This is rarely on a specification sheet and is worth looking for in a review that tested it.

The panel technology sets the floor

Worth knowing so you calibrate expectations rather than settings.

Different panel technologies have genuinely different transition characteristics, and the slow transitions — typically the dark ones — are where smearing is visible regardless of tuning. Overdrive can only push what the liquid crystal is physically able to do.

That is why some panels look excellent in bright motion and smear noticeably in dark scenes, and no setting resolves it.

Test it yourself, in five minutes, for nothing

The only reliable answer, and it needs no equipment.

Run a moving-object motion test in a browser, cycle through the overdrive settings, and watch the edges of the moving object rather than the object. Look for a dark trail behind it and a pale halo in front. Pick the setting with the least of both.

Then repeat at a lower refresh rate if you use variable refresh rate, because that is where a badly-tuned monitor gives itself away.

The order to work in

1. Find the overdrive control. It is often named something unhelpful.
2. Open a motion test and set it moving at a moderate speed.
3. Step through every setting, watching the leading and trailing edges.
4. Pick the setting with the least combined smear and halo — usually not the highest.
5. Repeat at a lower refresh rate if VRR is on.
6. Leave it there. This is a set-once adjustment.

The mistake to avoid

Buying on the response-time figure. It is measured on the panel's easiest transition, at its most aggressive overdrive, with a window that excludes the slow tail — three choices that all push it downward. Two monitors quoting the same number can look completely different in motion, and the one quoting the larger number is sometimes the better performer, so the figure cannot do the job it is printed for.

The second mistake is turning overdrive up because more sounds better. The top setting is generally there to produce the specification rather than to be used, and the pale halo it introduces is more visually intrusive than the mild smear it removed — which is why the fault most people notice after buying a fast monitor is one they created in the menu. The related question of what the two headline numbers do settle is in refresh rate vs resolution.