This ghosting test moves a small craft across three lanes at once, one on a dark background, one on mid grey and one on light grey, because ghosting and overshoot look different on each. A ruler at the top travels with the craft, so you can read how many pixels a trail runs behind it, by eye or in a photo. Use it as a ghosting test online to tune your monitor's overdrive setting, to compare two monitors, or to check a new screen before the return window closes. It works with LCD, OLED and mini LED monitors, laptops and TVs, on Windows, Mac, ChromeOS and Linux.
How to run the ghosting test
- Let the test measure your refresh rate for two seconds, and check that Skipped frames reads 0.
- Fix your eyes on the craft and follow it across the screen. Do not look at one spot; let your eyes track the motion, the way you follow a target in a game.
- Look behind the craft in each lane. Note a dark smear, a bright edge or a colored fringe.
- Change Speed to 1440 or 1920 pixels per second if the trail is hard to see.
- Switch Object to Bar for a plain edge, or Text to see how scrolling text smears.
- Open the monitor's menu and change the overdrive setting while the test runs. Compare each level.
What the artifacts look like
| What you see | Name | Cause | Fix |
|---|---|---|---|
| A dark or grey smear behind the craft | Ghosting | Pixels change too slowly | Raise overdrive one level |
| A bright, white or colored edge behind it | Overshoot, inverse ghosting | Overdrive pushes pixels too far | Lower overdrive one level |
| Long dark trails on the Dark lane only | Black smear | Slow dark transitions, common on VA panels | Raise overdrive, raise brightness a little |
| Even softness on both edges | Motion blur | Each frame is held on screen | Higher refresh rate or a strobing mode |
| A second, fainter craft beside the first | Strobe crosstalk | A strobing backlight out of step with the panel | Change the strobe setting or turn it off |
The Expected blur readout shows how much softness is normal at your speed and refresh rate. On a 144 Hz screen at 960 pixels per second it is about 7 pixels. A trail much longer than that is ghosting on top of normal blur.
Tune overdrive to stop ghosting
Overdrive briefly drives each pixel harder than needed so it reaches its new color faster. Too little leaves a trail; too much causes overshoot. Brands give the setting different names: Overdrive, Response Time, OD, Trace Free on ASUS and AMA on BenQ.
- Run this test at your monitor's top refresh rate and 960 pixels per second.
- Open the monitor's menu, usually under Gaming or Picture, and set overdrive to its lowest level. Note the trail on the Grey lane.
- Step up one level at a time. The trail shortens.
- Stop at the level just before a bright edge or colored halo appears behind the craft. That is the best setting for this refresh rate.
- Check the Dark and Light lanes too. The best compromise has short trails and no halo on all three.
Overdrive tuned for 144 Hz can overshoot when the frame rate falls to 60, which is why ghosting can get worse when a game slows down. Monitors with variable overdrive adjust for this; on others, a lower level often looks better if your games run well below the top refresh rate. To see the frame rate you are tuning for, check the 144hz test first.
Ghosting in dark scenes
If the trail is long on the Dark lane but short on the Grey and Light lanes, you are seeing the slow dark transitions of a VA panel. Raising overdrive helps a little, and so does raising brightness or the black level slightly, since VA pixels are slowest close to black. It is a trait of the panel type, so expect some of it on every VA monitor. IPS and OLED panels show far less.
Measuring the trail with a camera
Your eyes are the quickest judge, but a photo lets you compare settings side by side. Reviewers use a camera that slides along with the motion, called a pursuit camera:
- Leave Camera guide ruler on and set the speed to 960 pixels per second.
- Mount a phone on a rail or a long ruler, and set it to a shutter of 1/30 second or slower.
- Slide the phone along the screen at the same speed as the craft and take photos as it passes.
- Keep the photos where the ruler's numbers are sharp. Sharp ticks mean the camera matched the craft's speed.
- Read the length of the trail against the ruler. The 0 mark sits at the craft's front edge and the numbers count pixels behind it.
Ghosting on a TV or laptop
TVs add motion smoothing and noise filters that smear moving objects, so switch the TV to Game or PC mode before you judge it. Gaming laptops often hide overdrive in the maker's app rather than a monitor menu, for example Panel Overdrive in ASUS Armoury Crate or the overdrive switch in Lenovo's own app on Legion laptops (Lenovo Vantage on many models). Office laptops usually have no overdrive control at all.
When ghosting is a fault
Most ghosting is a property of the panel, and warranties rarely cover it. A clear fault is a trail that appears only in one part of the screen, ghosting that got worse over time, or a monitor that looks far worse than reviews of the same model. Run the ufo test and this test side by side with another monitor if you can, and return a new monitor within the return window if it does not match its reviews.
What a browser ghosting test cannot measure
This test shows ghosting; it cannot measure response time in milliseconds, because that needs a light sensor and an oscilloscope. It also does not measure input lag, the delay between a click and the screen changing, which the input lag test monitor page covers. Check that your screen runs at its full rate on the refresh rate test before tuning overdrive, since the right setting depends on it.
Ghosting test questions
What is monitor ghosting?
Ghosting is a faint trail that follows moving objects because the screen's pixels take too long to change color. It shows most on LCD monitors, worst of all on VA panels in dark scenes. It is different from motion blur, which every LCD and OLED screen has and which spreads evenly over both edges of a moving object.
How do I fix ghosting on my monitor?
Set the monitor's overdrive, also called Response Time or OD, to the level with the shortest trail and no bright halo, usually the middle one. Run the monitor at its top refresh rate, and on a TV switch to Game mode. If ghosting stays, it is a trait of the panel rather than a setting.
Is monitor ghosting normal?
Some is. Most LCD monitors leave a short trail at high speed, and VA panels smear dark colors. A trail far longer than reviews of the same model show, or one that appears only on part of the screen, is worth taking up with the seller while you can still return it.
Do OLED monitors have ghosting?
Almost none. OLED pixels change in well under a millisecond, so there is no trail. OLED still shows motion blur from holding each frame on screen, which only a higher refresh rate or black frame insertion reduces.
What is inverse ghosting?
Inverse ghosting, or overshoot, is a bright or colored outline behind a moving object. It appears when overdrive pushes the pixels past their target color. Turn overdrive down one level to fix it.
Can a bad cable cause ghosting?
Not on HDMI or DisplayPort. A failing digital cable causes sparkles, black flashes or no signal, never trails. On an old analog VGA cable, a faint copy of text offset to the right is also called ghosting; a digital cable fixes that.