Monitor Response Time & Ghosting Test
This monitor ghosting test moves a UFO across your screen at a fixed speed so you can see what your panel does with motion: the smeared trail behind a slow pixel, the bright halo of too much overdrive, or a clean edge if the display keeps up. Track the UFO with your eyes, change your response-time setting, compare. Nothing to install, and it is the fastest way to find the overdrive preset your screen looks best on.
What display ghosting actually is
Ghosting is a faint copy of a moving object trailing behind it, usually darker or washed out. It appears because a pixel did not finish changing colour before the next frame arrived.
An LCD pixel is a liquid crystal twisting to let more or less backlight through, and that twist takes time. A 144 Hz monitor gives each frame 6.9 ms; at 240 Hz it is 4.2 ms. If a transition needs 10 ms, the pixel is still mid-change when the next frame is drawn, and the leftover brightness is the trail. That is why a screen can look clean at 60 Hz and smear at its top refresh rate.
One thing to clear up, because the word is overloaded: display ghosting has nothing to do with keyboard ghosting. They share a name and nothing else — one is liquid crystal changing state, the other is a key matrix dropping keypresses. This page is only about the screen, one part of a full monitor test.
Why the UFO test works
The UFO pattern moves at a constant speed, which lets your eyes do the measuring. When you track a moving object your eyes glide with it, and your retina holds each pixel's output for as long as that pixel is under your gaze, so anything the pixel has not finished doing gets smeared across your vision. Only steady, predictable motion shows this.
Two rules make a monitor ghosting test trustworthy. Follow the UFO with your eyes: if you stare at a fixed point and let it fly past, you are seeing the stroboscopic stepping of a sample-and-hold display — separate copies rather than a smear, and not ghosting. And compare rather than score: eyes are good at spotting that B is worse than A, bad at putting a number on either.
Response time, refresh rate and input lag are three different numbers
- Refresh rate (Hz) — how often a new frame is drawn. 144 Hz means one every 6.94 ms. It sets the budget.
- Response time (ms) — how long a pixel takes to change colour, and therefore whether it fits inside that budget. Ghosting is what you see when it does not.
- Input lag — the whole delay from mouse movement to light reaching your eyes, including the GPU and the monitor's own processing.
Trails behind moving objects mean response time. A floaty, delayed feel means input lag. Motion that jerks or repeats is frame delivery, not the panel. Fixing the wrong one wastes money.
Overdrive, and why more is not better
Overdrive is the monitor overvolting a pixel to make it change faster — aiming past the target so it arrives on time. It hides in the OSD under Response Time, Overdrive, OD or Trace Free, with presets like Off / Normal / Fast / Fastest.
Push it too hard and the pixel overshoots before settling back, which appears as a bright or inverted halo around the moving object: inverse ghosting, also called overshoot or coronas. It is usually more distracting than the smear it replaced, because the artefact is brighter than the background rather than dimmer.
Tuning takes two minutes. Set the monitor to the refresh rate you actually use, since overdrive is tuned per refresh rate. Step through the presets while watching the UFO and keep the lowest one that removes the long trailing smear, backing off a step the moment halos appear. With adaptive sync the frame rate keeps moving, so unless the monitor has variable overdrive, pick the preset that behaves best mid-range. Overdrive does not wear the panel out; the worst it does is look bad.
VA smearing, IPS and OLED
Panel technology sets the ceiling, and no menu setting moves it.
- VA — best contrast, slowest dark transitions. Near-black to mid tone can take several times longer than a mid-to-mid change, producing the notorious black smear in night scenes. It is a property of the panel, not a defect, and overdrive only partly hides it.
- IPS — faster and more even, so trails are shorter and colour-neutral. Its typical failing is the opposite one: factory overdrive that overshoots on the fastest preset.
- OLED — transitions in microseconds, so pixel-response ghosting does not exist. Remaining blur is persistence, cured by more Hz, and these panels have no overdrive setting.
If dark scenes look wrong even when nothing moves, a monitor color test shows whether you are seeing banding or black crush rather than smearing.
GtG vs MPRT: what "1 ms" on the box means
Both numbers are real, they measure different things, and boxes rarely say which is quoted. GtG (grey to grey) is pixel transition time, measured from 10% to 90% of the change, at the most aggressive overdrive setting, on whichever colour pair performs best. Real transitions — especially dark ones on VA — are often several times slower, which is how a "1 ms" monitor can visibly smear.
MPRT (moving picture response time) describes perceived persistence instead of pixel speed. Reaching 1 ms MPRT almost always means backlight strobing: the backlight blanks between frames so each image is shown for a shorter slice of time. It genuinely cuts blur, at the cost of brightness, and usually cannot run alongside adaptive sync. A display can be 1 ms MPRT and 8 ms GtG at once without anyone lying.
What this test can and cannot tell you
A browser can put motion on your screen, but it cannot hold a photodiode against the panel. No web page can measure your pixel transition time in milliseconds, and any site printing one is estimating. What a browser monitor ghosting test gives you is a controlled, repeatable moving target for comparing settings on your own display.
- The page draws frames at your current refresh rate, so set the monitor to the rate you want to judge and close anything heavy first.
- Screenshots and ordinary phone photos will not show ghosting; pan a phone camera along with the UFO at a 1/30 s exposure, or trust your eyes.
- Results compare settings on one screen; they do not compare with review numbers from lab equipment.
- Ghosting only exists while something moves. A faint image that stays on a still screen is retention or a stuck sub-pixel instead, so run a dead pixel test to check.
Frequently asked questions
Why do I get a huge amount of ghosting at 240Hz but much less at 60Hz?
Because a 240 Hz frame lasts 4.2 ms and your pixels need longer than that to finish changing colour, while a 60 Hz frame gives them 16.7 ms and they complete comfortably. The panel is the limit, not the GPU. Raise the overdrive preset one step at a time at 240 Hz and stop before bright halos appear — that is usually the best the monitor can do.
Is my monitor defective if it has ghosting and smearing?
Almost certainly not. Ghosting is how fast the panel's pixels can change, so a slow monitor smears from the day it leaves the factory and every unit of that model does the same. Swapping the cable, the port or the PC changes nothing, which is the usual clue. A genuine fault looks different: dead pixels, a permanent burned-in shape, flicker, or lines that stay put when nothing is moving.
Is there any disadvantage to setting my monitor's response time to Fastest?
No damage and no shortened lifespan — the only cost is picture quality. Overdrive pushes extra voltage at the pixel so it changes faster, and on the highest preset it usually overshoots, leaving a bright or inverted halo around moving objects. That artefact is often more distracting than the smear it removed. Start at Fastest, and if you see halos on the UFO, drop to the next preset down.
What is the difference between GtG and MPRT, and which one is better?
GtG measures how long a pixel takes to change colour; MPRT measures how long the image stays visible to your eye, which is what motion blur actually is. Neither is better — they describe different problems. GtG is quoted from the best-case transition at maximum overdrive, and 1 ms MPRT is normally achieved with backlight strobing. A monitor can honestly claim 1 ms MPRT while its real GtG is 8 ms.
Are all VA panels that bad with black smearing?
All VA panels smear on dark transitions to some degree, but the amount varies a lot by model, not by luck of the draw. Dark-to-light changes are the slowest on VA, so the trail shows up in night scenes and dark games and barely at all on bright desktops. Overdrive reduces it only slightly. If dark smearing bothers you, panel type is the fix — IPS or OLED — not a setting.
How do I tell whether I am seeing ghosting or something else, and how much is too much?
Ghosting follows the object as a smeared copy and only exists while something moves; if you track the UFO with your eyes and the trail moves with it, that is ghosting. Separate copies spaced apart while you stare at a fixed point are a stroboscopic effect, not a panel fault. Too much is simply the point where you notice it in normal use — there is no threshold, so tune the overdrive until it stops distracting you.
Why do I see white shadows around objects when I move in a game?
That is inverse ghosting — the overdrive setting is too aggressive, so pixels shoot past their target brightness and settle back, leaving a pale outline ahead of or behind the object. It is not a cable fault and not the GPU. Lower the monitor's response time or overdrive preset by one step and the halo disappears; if a lower setting brings back dark trailing, the preset in between is usually the right one.