How to read your result
Quick answer: A dark or faint trail behind the shape is ghosting: raise the monitor’s overdrive one step. A bright halo or a light outline behind it is overshoot: lower overdrive. Even blur on both edges is normal sample-and-hold blur, and a higher refresh rate is the fix. Jumps or stutter mean skipped frames, so check your Hz.
| What you see | What it means | Next step |
|---|---|---|
| A dark or faint copy trailing the shape | Ghosting. The pixels change color too slowly | Raise overdrive one step in the monitor menu. Monitor ghosting fix guide |
| A bright halo or light outline behind it | Overshoot (also called coronas or inverse ghosting). Overdrive is set too high | Lower overdrive one step and look again |
| Both edges soft, about the same amount | Sample-and-hold motion blur. Normal on LCD and OLED | Run a higher refresh rate, or try your monitor’s motion blur reduction mode if it has one |
| Trail on one band only, often the dark one | The panel is slower for some shade changes than others | Pick the overdrive setting that looks best on the background you see most in games |
| The shape jumps or stutters | Skipped frames or a low refresh rate | Check the reading above, then run the refresh rate test |
Fix guides by device: monitor · laptop · TV · phone and tablet
How to use the ghosting test
-
Set the monitor to its full refresh rate first. A 144 Hz screen left at 60 Hz blurs far more, and that hides what overdrive is doing.
-
Press Start, then Full screen if you can. Keep the speed at 960 px/s to begin with.
-
Follow the shape with your eyes across each band. Look at the trailing edge, the side it moves away from.
-
Open the monitor menu and change overdrive one step at a time. Watch the test after each change. Switch the shape between white and black too, since some trails only show one way round.
Takes a couple of minutes. Many monitors only offer a handful of overdrive steps, so there isn’t much to try.
Ghosting, overshoot or motion blur?
Three different things, and they look alike at first glance.
Ghosting is a trail. LCD pixels need time to change color, and they’re often quicker in one direction than the other, so the trailing edge smears. Blur Busters’ overdrive explainer puts it down to those uneven pixel transitions.
Overshoot is the opposite mistake. Overdrive pushes extra voltage to speed pixels up. Push too hard and they pass the target shade, which shows as a bright halo or outline behind the shape. Blur Busters calls these coronas, also known as inverse ghosting.
Motion blur happens even when pixels switch almost instantly. Each frame stays lit until the next one, and your eyes keep moving, so the image smears. Per Blur Busters’ GtG versus MPRT FAQ, even a 60 Hz OLED holds each frame for at least 16.7 ms. Doubling the frame rate and refresh rate halves that blur.
The “expected blur” figure above uses the Blur Busters Law: 1 ms of persistence gives 1 pixel of blur per 1,000 pixels per second of motion. It’s the minimum for your current refresh rate, assuming instant pixels. If what you see is far wider, slow pixels are adding to it.
How to fix ghosting on a monitor
How to fix monitor ghosting: the full guide
Overdrive is the main setting, and every brand names it differently. Blur Busters lists ASUS “Trace Free”, BenQ “AMA” and Acer “Overdrive”. Others call it Response Time.
-
Start in the middle. Low overdrive leaves ghosting and high overdrive adds coronas. A middle step is often the best trade (Blur Busters found that on an ASUS monitor), though it varies by model.
-
Retest at the refresh rate you play at. Overdrive can behave differently at different refresh rates, so a setting that looks clean at 144 Hz may not at 60 Hz.
-
Watch the coronas on BenQ and ZOWIE. ZOWIE’s AMA FAQ covers the shadows that can appear when AMA is set high.
-
Try the motion blur reduction mode if your monitor has one. It strobes the backlight, so skip it if flicker bothers you, and expect a dimmer picture.
Ghosting that’s still bad on every setting can just be how the panel is. Some buyers return the monitor at that point, and if it’s inside the return window that’s an option.
What this test can’t do
It can’t measure response time in milliseconds. A browser doesn’t know how fast pixels change, only when it drew a frame. So this is a visual check that you judge by eye.
Browsers also skip frames when the computer is busy, which looks like stutter rather than ghosting. Watch the skipped frames counter. For photos you can compare between settings or monitors, TestUFO’s ghosting test supports a pursuit camera setup and is the reference tool for this.
Frequently asked questions
What does a monitor ghosting test show?
It moves a shape across dark, mid and light backgrounds so you can see trails, bright halos or plain motion blur. That tells you whether to change the monitor’s overdrive setting, raise the refresh rate, or accept normal blur.
Is ghosting the same as motion blur?
No. Ghosting is a trail left by pixels that change color too slowly. Motion blur also happens on screens with very fast pixels, because each frame stays on screen until the next one. Blur Busters explains the difference as GtG versus MPRT.
What overdrive setting should I use?
Usually the middle one. Low overdrive leaves ghosting, high overdrive adds bright halos called coronas or inverse ghosting. Step through each setting with this test running and keep the one where both are smallest.
Why does the test look blurrier on a 60 Hz screen?
Each frame stays on screen longer. Blur Busters puts it as 1 ms of persistence equals 1 pixel of blur per 1,000 pixels per second of motion, so at 60 Hz a 960 px/s shape smears by about 16 pixels.
Can a website measure response time?
No. A browser can’t see how fast pixels change. This test shows the artifacts so you can judge them by eye. For photos you can compare, TestUFO’s ghosting test supports a pursuit camera setup.
Sources
- Blur Busters: LCD Motion Artifacts, Overdrive, checked 2026-10-25.
- Blur Busters: GtG versus MPRT, FAQ about display pixel response, checked 2026-10-25.
- Blur Busters Law: the journey to 1000Hz displays, checked 2026-10-25.
- TestUFO: Ghosting test and pursuit camera, checked 2026-10-25.
- ZOWIE (BenQ): Shadows when using AMA, checked 2026-10-25.