Ghosting is the visible smear that trails a moving object on your screen. Move your cursor quickly across the desktop — if you see a faint trail behind it, that is ghosting. Spin the camera in a fast-paced shooter — if the world smears instead of staying sharp, that is ghosting. It is the most visible artefact of slow pixel response, and it is the single biggest reason budget monitors feel worse than premium ones, even when both claim the same refresh rate and resolution.
The cause is mechanical. Liquid crystal pixels take time to rotate from one orientation to another — anywhere from 1 ms on a fast IPS gaming panel to 25 ms on a budget VA panel. While the pixel is mid-rotation, it shows a mix of the old and new colours. Your eye, which integrates what it sees over about 80 ms, blends these intermediate states into a smear that follows the object. The faster the object moves and the slower the pixel response, the longer the smear.
How pixel response time works
Pixel response time is the time it takes for a pixel to change from one colour to another. It is usually quoted in milliseconds and is one of the headline specs on monitor boxes. But there are several important caveats:
- Spec sheets quote grey-to-grey (GtG) response. GtG is the average transition between two similar grey levels, which is the fastest transition the panel can do. Real-world transitions between saturated colours are typically 3-5× slower.
- Response time depends on direction. Black-to-white is slower than white-to-black. Both are slower than grey-to-grey. Some transitions on VA panels can take 25-30 ms in worst case.
- Response time varies with overdrive. Without overdrive, panels run at their natural speed (often slower than the spec). With overdrive, panels hit their advertised numbers — sometimes faster, sometimes with overshoot side effects.
- Response time varies with temperature. Cold panels are slower. This is usually invisible but can affect very cold rooms.
What overdrive does (and why it can backfire)
Overdrive (also called Response Time, OD, or RT in monitor menus) pushes extra voltage through the liquid crystal to make it rotate faster. A well-tuned overdrive setting can cut response time in half with no side effects. A badly-tuned one causes overshoot — the pixel rotates past the target colour and bounces back, creating a bright or coloured halo around moving objects.
The right overdrive setting depends on your refresh rate. What works at 60 Hz might overshoot at 144 Hz. Many modern monitors handle this automatically with a variable overdrive feature (sometimes called Adaptive Overdrive), but most still require manual tuning. The general rule: pick the lowest overdrive setting that produces no visible smear on the ghosting test. Anything higher causes overshoot without further reducing blur.
| Overdrive setting | What you see | Best for |
|---|---|---|
| Off | Dark smear behind moving objects | Slow 60 Hz office monitors where ghosting is mild anyway. |
| Low / Slow | Slight reduction in smear, no overshoot | Casual gaming on 60 Hz monitors. |
| Normal / Medium | Significant smear reduction, minimal overshoot | The sweet spot for 144 Hz gaming on most panels. |
| High / Fast | Maximum smear reduction, slight overshoot | Competitive gaming on 240 Hz monitors with fast panels. |
| Extreme / Max | Heavy overshoot — bright halos around objects | Almost never recommended. Marketing-driven setting that looks worse, not better. |
Panel types and ghosting
Different panel technologies have different ghosting characteristics. Knowing your panel type helps you set realistic expectations:
| Panel type | Typical response | Ghosting behaviour | Best for |
|---|---|---|---|
| TN (Twisted Nematic) | 1-3 ms GtG | Minimal ghosting, no overshoot at moderate overdrive. Colours are washed out. | Competitive esports where speed matters more than image quality. |
| IPS (In-Plane Switching) | 3-5 ms GtG | Mild ghosting on budget models, minimal on premium. Good colour accuracy. | Most gamers. The best all-round panel type. |
| VA (Vertical Alignment) | 4-8 ms GtG, 20-30 ms black-to-dark | Heavy black smearing in dark scenes. High contrast but slow dark transitions. | Single-player games where contrast matters more than speed. |
| OLED | <0.1 ms GtG | No traditional ghosting. Sample-and-hold blur is the only artefact. | Premium gaming where image quality and response both matter. |
How to fix ghosting on your monitor
If our ghosting test shows visible smearing, here is the troubleshooting order:
- Check the OSD. Open your monitor's on-screen display and find the Response Time, OD or Overdrive setting. If it is Off, set it to Normal or Medium.
- Try different overdrive levels. Run the ghosting test at each setting from Low to Extreme. Pick the lowest setting that produces no visible smear. If you see bright halos, you have overshoot — drop down a level.
- Check your refresh rate. Higher refresh rates reduce motion blur per frame even with the same pixel response. Make sure you are actually running at your monitor's max refresh rate using our refresh rate test.
- Try motion blur reduction. Some monitors have a backlight strobing mode (ULMB, ELMB, MBR, LightBoost) that mimics CRT motion clarity. It dims the screen and can cause flicker, but eliminates most motion blur.
- Consider a panel upgrade. If you are on a budget VA panel with heavy black smearing, no setting will fix it. A fast IPS panel is the most cost-effective upgrade; OLED is the best if budget allows.
Sample-and-hold blur — the OLED gotcha
OLED panels have essentially perfect pixel response — under 0.1 ms, faster than any LCD could hope to be. Yet OLEDs still show motion blur. Why? Because of sample-and-hold blur, a perceptual phenomenon that has nothing to do with pixel response.
Here is the mechanism: when a frame is displayed, the eye tracks the moving object smoothly. If the frame is held static for the entire refresh (which LCD and OLED both do), the eye sees the object stationary while the eye is moving — which the brain interprets as blur. The only way to eliminate sample-and-hold blur is to display each frame for a very short time (backlight strobing on LCDs, BFI on OLEDs) or to increase the refresh rate so each frame is held for less time.
This is why a 60 Hz OLED has more motion blur than a 240 Hz LCD, even though the OLED's pixel response is 100× faster. Refresh rate matters more than pixel response for sample-and-hold blur. The ideal is a 240 Hz+ OLED with BFI enabled — perfect pixel response, very short hold time, and minimal motion blur.