A level 160 block crosses a level 128 field, a change of 32 levels in the middle of the range. With room above the block and below the field, overshoot in either direction has nowhere to hide.
Pattern
On a screen that holds each frame, your eye smears a shape at this speed across about 20 pixels.
Space pauses. The arrows change speed. F goes full screen.
Slow pass, 600 pixels a second10 pixels a frame at 60 Hz, 5 at 120 Hz and 2.5 at 240 Hz. The smear your own eye tracking adds is as wide as one frame of travel, so at this pace a thin halo is not buried in it.
Steady pass, 1,200 pixels a second20 pixels a frame at 60 Hz, 10 at 120 Hz and 5 at 240 Hz. The page opens here: quick enough to stretch a halo into a band you can see, slow enough to follow the block with your eyes.
Fast pass, 2,400 pixels a second40 pixels a frame at 60 Hz, 20 at 120 Hz and 10 at 240 Hz. Use it on a fast screen to tell two neighboring overdrive levels apart. At 60 Hz the block jumps too far each frame to judge.
Show all 19 speeds, patterns and checks (16 more)
Blocks that show overshoot 6
Gray block one step lighter than the fieldA level 160 block crosses a level 128 field, a change of 32 levels in the middle of the range. With room above the block and below the field, overshoot in either direction has nowhere to hide.
Gray block one step darker than the fieldThe same step the other way: level 96 on level 128. Each edge now asks the pixels for the opposite change. A monitor can be clean on the lighter block and overshoot on this one, so run both at every overdrive level.
Four small steps round mid grayFour blocks at levels 96, 112, 144 and 160 cross the level 128 field together: steps of 16 and 32 levels each way. Compare the lanes in one pass and note which block, if any, drags a halo or a shadow.
Pale gray block on whiteLevel 208 on level 255, the bright end of the range, as when a pale panel scrolls over a white page. White is the top level, so nothing here can turn brighter than the field. Look for a dark edge instead.
Deep gray block on near blackLevel 48 on level 16, the dark end. Dim the room. An edge brighter than the block is overshoot. A long smoky tail darker than the block is slow pixels, which is black smearing and not overdrive.
Color blocks on mid gray, cyan, magenta and yellowEach block has two channels fully on and one off, so at every edge one sub-pixel moves the opposite way from the other two. If the three overshoot by different amounts, the trail takes a tint found in neither block nor field.
What you see behind the block 6
A dirty shadow trailing the lighter blockA band behind the block that is darker than both the block and the field: on their way back the pixels fell below the field's shade before settling, which some call undershoot. Slow pixels cannot make that. Lower overdrive one step and run the same block again.
A pale halo trailing the darker blockThe same fault in the other direction: a band behind the block that is brighter than both the block and the field, where the pixels rose past the field's shade. This is the bright form of overshoot. Lower overdrive one step.
A tinted fringe on the colored blocksA trail of a color that neither the block nor the gray field holds. Overshoot halos can be colorful. Treat it like a pale halo: one overdrive step down, then run the two gray blocks again.
A soft tail no brighter than the blockA fading tail whose shade lies between block and field is ordinary trailing: the pixels are late, not overshooting. Overdrive is too low for that pair of shades. Go up one step and check that no halo comes with it.
The same narrow blur at every overdrive levelA soft edge about one frame of travel wide that no overdrive level changes is not the panel. The screen holds each frame still while your eyes keep moving. A higher refresh rate narrows it; overdrive cannot.
A halo in games that this page never showedWith a variable refresh rate the screen follows a game's frame rate down, and a level that was clean at the top rate then overshoots for longer. This page draws at the rate the browser is given, so it cannot show that case.
What to change, in order 4
Find overdrive in the monitor's menuThe setting lives in the monitor's own menu, not in the operating system. Menus list it as Overdrive, Response Time or under a maker's own name. Note the level it is on before you change anything, so you can come back to it.
Step overdrive down until the halo goesLower the level one step, press Start again on the same block at the same speed, and look behind it. Keep the highest level that leaves both mid-gray blocks clean: no halo, no shadow, and the shortest tail.
Repeat at each refresh rate you useOverdrive is balanced for the monitor's maximum refresh rate, so a level that is clean there can overshoot at a lower one. If you also run the screen at 60 Hz, set that rate and run the same blocks again.
Variable refresh rate: one level lower for gamesWith a variable refresh rate, monitor reviewers advise dropping to a lower overdrive level when a game's frame rate sits well below the maximum. Some monitors retune overdrive by themselves as the rate moves and need no change.
How this list was compiled: The speeds, patterns, signs and settings are this site's own, and the moving shapes are plain blocks. Every figure was computed: pixels a frame are speed divided by refresh rate (600 pixels a second is 10 at 60 Hz, 5 at 120 Hz and 2.5 at 240 Hz), and the gray levels are whole steps of 16 and 32 from level 128. That response time compensation is also known as overdrive, and that it sends a higher first voltage and then moderates it so the liquid crystal turns faster, is from https://en.wikipedia.org/wiki/Response_time_compensation. That a display holds each frame still while the eyes keep tracking, which smears the image by one frame of travel, is from https://en.wikipedia.org/wiki/Display_motion_blur. That a variable refresh rate display matches its refresh rate to the frame rate it is sent is from https://en.wikipedia.org/wiki/Variable_refresh_rate. Overshoot and inverse ghosting from an aggressive voltage surge, its dark form (dirty or shadowy trailing darker than the object or the background, which some call undershoot) and its bright form (halo trails brighter than both, which can be colorful), certain transitions being more affected than others, overdrive being balanced for the maximum refresh rate, overshoot that persists for longer as a variable refresh rate falls and the advice to switch to a lower overdrive level then, monitors that retune overdrive as the rate changes, and OLED panels needing no aggressive overdrive, are from https://pcmonitors.info/articles/factors-affecting-pc-monitor-responsiveness/. All read 2026-10-06. The page measures nothing: a browser cannot time a pixel, so no response time and no amount of overshoot is given, and every sign is judged by eye. Licence: own work
How it works
This monitor overdrive test slides gray blocks a small step lighter or darker than their background. A halo brighter than both shades, or a shadow darker than both, is overshoot: overdrive set too high.
Read the full guide
A monitor overshoot test in four steps
1. Press Start, follow the block with your eyes and look just behind it.
2. A pale halo or a dark shadow is overshoot: lower overdrive one step in the monitor's menu.
3. A soft tail no brighter than the block means overdrive is too low: go back up.
4. Keep the highest level that leaves both mid-gray blocks clean.
Questions and answers
What is overdrive on a monitor?
A way to speed up an LCD's pixels. The liquid crystal turns slowly, so the monitor sends each pixel a higher voltage than the new shade needs and then eases off. Set too strong, the pixel shoots past its target.
What is the difference between ghosting and overshoot?
Ghosting is a trail from pixels that change too slowly, and its shade lies between the moving object and the background. Overshoot, or inverse ghosting, is a trail brighter or darker than both, made by overdrive that is too strong.
Can a browser measure overshoot or response time?
No. A page can move a block and count the frames it draws, but it cannot see how a pixel changes between two shades. This test shows the blocks and names the signs; the reading is yours.
Do OLED monitors need an overdrive test?
Much less. OLED pixels change far faster than an LCD's and need no aggressive overdrive to keep up, so the halos this test hunts are an LCD fault first. The blocks still show any trail the screen makes.