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Monitor Response Time Test

Press Full Screen, watch the trailing edge of the moving box, and step through your monitor’s overdrive levels to find the one with clean edges and no halo. This is the real grey-to-grey behaviour — not the marketing “1ms”.

New to this? Here’s the plain-English version.

What this test is

A moving box that shows how fast each pixel can change colour — the thing that decides whether motion looks clean or smeared.

How it helps you

It helps you find your monitor’s best “overdrive” setting, so games and video look sharp instead of leaving trails — usually a free fix in your monitor’s menu.

What we’re checking

Whether moving objects leave a dark smear behind them (pixels too slow) or a bright halo ahead (overdrive pushed too far).

Look for ghosting or smearing as the screen switches between black and white.

A fast response time will result in a sharp, clean switch. Slow response times may show noticeable "ghosting" or smearing, where the previous image briefly persists.

Press F11 or Full Screen · ← → patterns · Esc to exit

How to Run the Test

Response time is most visible at medium-to-fast movement. Slow speeds hide pixel transitions; very fast speeds exaggerate overdrive coronas. Run the box at a moderate pace and judge the trailing edge.

  1. 1Launch fullscreen. Press Full Screen above. A box moves horizontally — use a medium-to-fast speed where transitions are easiest to judge.
  2. 2Watch the trailing edge. A clean, sharp trailing edge means fast pixel response. A dark smear behind the object means slow GtG.
  3. 3Cycle your overdrive levels. Open the OSD Response Time / Overdrive setting and step through each level while the test runs.
  4. 4Pick the cleanest level. Choose the setting with the least trailing and no bright halo ahead of the object.

GtG vs MPRT — The Spec That Actually Matters

Manufacturers advertise two different response-time numbers, and they measure completely different things. Knowing which one to trust is the difference between a monitor that looks clean in motion and one that smears despite its “1ms” sticker.

GtG — the one to trust

Grey-to-grey: how long a pixel takes to change shade. This is what produces (or prevents) the ghosting in this test. Fast GtG → clean edges. Slow GtG → visible trailing.

MPRT — the marketing one

Moving Picture Response Time: perceived blur from sample-and-hold, only reachable with a strobe backlight on. Always a lower number, so it becomes the headline “1ms”.

The trap:a monitor sold as “1ms MPRT” can have a real GtG of 8ms or more — enough to ghost noticeably. The test above shows you what your panel’s GtG actually does, regardless of the box it came in.

Response Time by Panel Type

PanelTypical GtGGhosting risk
TN0.5–2msVery low
Fast IPS / Nano IPS1–4msLow
Standard IPS4–8msLow–moderate
VA (grey)4–12msModerate–high on dark
OLED<0.1msEffectively none

VA carries the biggest caveat: its rated GtG measures a mid-grey transition, but the dark-to-grey transitions behind night-scene smearing can be several times slower. OLED has no liquid crystal, so response is effectively instant — its only motion caveat is static-image retention, which you can check with the burn-in test.

Dialing In Overdrive

Overdrive (Response Time / TraceFree / AMA) pushes extra voltage to switch pixels faster. Too little leaves a dark trail; too much overshoots into a bright halo. The two problems look opposite — here is how to read them:

Overdrive too low

  • Dark smear or shadow trailing behind the object
  • Worst on dark or high-contrast backgrounds
  • → Increase one level

Overdrive too high

  • Bright white halo/corona ahead of the object
  • Leading edge looks brighter than it should
  • → Decrease one level
  1. 1Start at the medium overdrive level.
  2. 2Run this test at a moderate speed.
  3. 3See dark trailing? Increase one level and retest.
  4. 4See a bright corona? Decrease one level.
  5. 5Optimal = minimal trailing AND no visible corona. Most panels land on Medium or High.

For a deeper look at each artifact type — dark ghosting, inverse-ghosting coronas, IPS trails, and VA smear — see the dedicated ghosting test.

Response Time FAQ

What is monitor response time?+
Response time is how long a pixel takes to change from one colour to another, measured in milliseconds. Faster response means less ghosting — the pixel finishes switching before the next frame arrives, leaving no visible trail of the previous colour.
What is the difference between GtG and MPRT?+
GtG (Grey-to-Grey) measures actual pixel transition speed — the spec directly responsible for ghosting you see in games and video. MPRT (Moving Picture Response Time) measures perceived blur from sample-and-hold and is only achievable with a strobe backlight active. GtG is the meaningful real-world number; MPRT is lower and used mainly in marketing.
Is a 1ms response time actually 1ms?+
Usually not in GtG terms. The advertised “1ms” is almost always MPRT with strobing enabled. The underlying GtG that controls real ghosting is typically 3–8ms on standard IPS and 4–12ms on VA dark transitions. TN and fast gaming IPS panels (LG Nano IPS, IPS Black) can hit genuine 1–4ms GtG.
How do I reduce ghosting with overdrive settings?+
Open your monitor’s OSD and find Response Time / Overdrive (called TraceFree, AMA, or OD depending on brand). Start at Medium, run this test, and adjust: increase a level if you see dark trailing, decrease a level if a bright halo appears ahead of the object. The target is clean edges with neither artifact.
Does response time matter for non-gaming use?+
For web browsing, office work, and normal-speed video: no, it is essentially irrelevant. Ghosting only shows during fast lateral motion. It matters for gaming, fast video scrubbing, and cursor-heavy work where you drag things quickly across the screen.
Why do VA panels smear in dark scenes?+
A VA panel’s advertised GtG usually measures a mid-grey transition. Its dark-to-grey transitions — the ones that dominate night-time game scenes — can be 3–5× slower, producing the characteristic grey-purple smear. It is a limitation of VA technology, not a defect. If you mostly play dark games, IPS or OLED avoids it.
What overdrive level should I use?+
Most monitors look best at Medium or High. Extreme/Maximum usually introduces inverse ghosting (a bright corona ahead of moving objects) that is more distracting than the trailing it removes. Use this test to find the highest level that still shows no corona.

Related Monitor Tests

Ghosting Test

Dark trails vs inverse-ghosting coronas

Refresh Rate Test

Confirm your true Hz first

Motion Blur Test

Sample-and-hold blur vs pixel ghosting

Checking a whole new panel?

Run the dead pixel test and browse the full monitor test suite.

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