Monitor Response Time Explained: GtG vs MPRT, 1ms vs 5ms, Overdrive, Ghosting and Input Lag

Every monitor specification sheet has a line for response time, and the number is almost always small and impressive: 1 ms, 2 ms, 4 ms, 5 ms. Gaming monitors advertise 1 ms in large letters. But anyone who has used a "1 ms" monitor and seen smeary trails behind moving objects knows the number does not tell the whole story. What does response time measure? Why can two monitors with the same figure look completely different? And how much does it matter for office work, films and games?

This guide gives monitor response time explained in plain language, with the arithmetic worked out, so you can read a specification sheet critically and avoid paying for numbers that do not help you.

We are City Gadgets Kenya, at New Alnoor Exhibition, Second Floor, Shop C7, Accra Road, Nairobi CBD, with same-day delivery in Nairobi and next-day delivery outside Nairobi. We stock office monitors and other displays, and we explain them honestly. Specifications below are general, "per the maker", and we confirm per unit.

The short version

• Response time is how quickly a pixel changes from one colour to another. Slow pixels leave trails or ghosts behind moving objects.
• GtG (grey to grey) and MPRT (moving picture response time) are two different measures. A "1 ms" claim is often MPRT with a special mode on, or the best-case GtG, not the typical performance.
• Response time works together with refresh rate. At 60 Hz each frame lasts about 16.7 ms. A pixel that needs longer than that to change will smear.
• Overdrive speeds up pixels, but too much causes overshoot, a bright or dark halo called inverse ghosting.
• Input lag is a separate thing: the delay between your action and the screen showing it.
• For office work and films, response time hardly matters. For fast games, it matters more, and panel type and tuning matter more than the headline number.

What is response time?

A screen is made of millions of pixels. When the picture changes, each pixel must change colour, and that takes a short time. Response time measures how long. If pixels are slow, the old picture lingers while the new one appears, and fast-moving objects leave a smear or trail behind them. This is ghosting or motion blur.

Response time is measured in milliseconds (ms), thousandths of a second. A smaller number means faster pixels.

GtG: grey to grey

The common industry measure is GtG. It records the time for a pixel to move between two shades of grey, for example from dark grey to light grey, usually between 10 and 90 per cent of the change. Makers often quote the fastest transition, or an average across several, measured with the most aggressive overdrive setting. A real picture contains many transitions, and the slowest ones, usually from dark to slightly lighter shades, can take several times longer than the best.

MPRT: moving picture response time

MPRT is a different measure, describing how blurred a moving object appears to your eyes. Many monitors reach a very low MPRT, such as 1 ms, by flashing the backlight off briefly between frames (backlight strobing). It works like a very short shutter and reduces perceived blur. The cost is lower brightness, possible flicker and the need to run at a fixed refresh rate, and the mode often cannot be combined with variable refresh rate. So a "1 ms (MPRT)" claim describes a special mode, not the normal behaviour of the pixels.

Why "1 ms" and "5 ms" are not directly comparable

A monitor claiming "1 ms GtG" and another claiming "1 ms MPRT" are describing different things. A monitor claiming "5 ms" may be a typical figure, and may actually look cleaner than a "1 ms" monitor with aggressive overdrive. Without independent measurements or a look at the screen in motion, the headline number is a weak guide.

Why refresh rate and response time go together

A monitor refreshes its picture a fixed number of times per second. Each refresh is a frame, and each frame lasts a certain time. We can calculate the frame time as 1,000 ms divided by the refresh rate in hertz.

These are our calculations. The idea: for a clean picture, pixels should finish changing well within one frame time. If a pixel needs 8 ms to complete a typical change, a 60 Hz monitor (16.67 ms frames) copes, a 144 Hz monitor (6.94 ms frames) starts to smear, and a 240 Hz monitor (4.17 ms) would blur heavily. That is why high-refresh-rate monitors need faster pixels, and why 240 Hz on a slow panel is wasted. Read our refresh rate explained article for the full picture.

For an office monitor at 60 or 100 Hz, such as the 100 Hz IPS models in our range from Dell and HP, per their makers, frame times of 16.67 ms and 10 ms are generous, and a typical response time of a few milliseconds is plenty. We confirm the exact specification per unit.

Overdrive, overshoot and inverse ghosting

To speed up slow pixels, monitors use overdrive: they briefly apply a stronger voltage than needed to push the pixel to the target faster. Done well, it cuts smearing. Done badly, the pixel overshoots its target and then settles back, leaving a bright or dark halo around moving objects. This is called overshoot, inverse ghosting or coronas.

Many monitors offer overdrive levels such as Off, Normal, Fast and Extreme. The fastest setting often gives the best "1 ms" number and the worst overshoot. A good approach is to try the levels with a moving test and choose the one that looks cleanest, which is often a middle setting. Variable refresh rate can complicate this, because the ideal overdrive depends on the refresh rate, and cheaper monitors tune it for only one rate.

How panel type affects response time

Panel technology strongly influences how fast pixels can change. For more on the panel types, read our IPS vs VA vs OLED explained article.

• TN panels have historically been the fastest LCDs, with weaker colours and viewing angles.
• IPS panels offer good colour and viewing angles, and modern fast IPS panels respond quickly. Office IPS monitors are usually tuned for balance and not for the fastest motion.
• VA panels have strong contrast, but dark transitions can be slow, which causes smearing in dark scenes, especially on cheaper models.
• OLED panels switch pixels almost instantly, with response times well under a millisecond per the makers, which gives very clean motion. OLED's other trade-offs are covered in our QLED vs OLED vs mini-LED explained article.

A specification sheet number cannot capture this. Reviews that measure real transitions, and your own eyes, are better guides.

Input lag: the other delay

Response time is not the only delay between you and the screen. Input lag is the total time from when you press a button or move the mouse to when the result appears. It has several parts:

1. Your input device, such as the mouse or keyboard, including wireless latency.
2. The computer or console processing the action and rendering the frame.
3. The cable and signal transfer.
4. The monitor's own processing, where it scales, enhances and prepares the picture.
5. The pixel response, which is the response time.

Monitors with heavy image processing add lag, and TVs often add more than monitors unless they are in game mode. A monitor can have fast pixels and still have noticeable input lag if its processing is slow, and a monitor with moderate pixels can feel responsive if its processing is quick. For competitive gaming, low input lag matters as much as response time. Most office users never notice it. If you game on a TV, switch to game mode to reduce lag. Our HDMI 2.1 explained article describes ALLM, which does this automatically on supported devices.

Wireless mice add a little delay too. For fast games, a wired mouse or a low-latency wireless model is better. See our best gaming mouse guide.

Ghosting, blur and strobing: what you actually see

Different problems look alike on screen, so it helps to name them.

Ghosting (slow pixels). A faint trail follows a moving object, like a comet tail. It is worst when dark objects move over light backgrounds on a slow VA or IPS panel.

Overshoot (inverse ghosting). A bright or dark halo leads or surrounds an object. It comes from over-aggressive overdrive.

Sample-and-hold blur. Even with instant pixels, an LCD or OLED holds each frame for the whole frame time, and your eyes, tracking a moving object, perceive blur. Higher refresh rates and strobing reduce this. This is why a fast OLED at 60 Hz still shows some motion blur.

Judder or stutter. Uneven frame delivery, which relates to frame rate and sync, not pixel speed. Variable refresh rate helps.

Tearing. A horizontal split in the picture when the frame rate and refresh rate do not match. Sync technologies help.

Knowing which problem you see tells you what to fix: overdrive, refresh rate, sync or the game's performance.

How to test response time yourself

You can judge a monitor's motion handling in minutes, in the shop or at home.

1. Use a motion test. Several motion-test pages and apps show moving objects across the screen, with a pursuit camera style test that lets you see trails. Run it at the monitor's native refresh rate.
2. Try the overdrive settings. Look for trails (too slow) and halos (too fast), and choose the cleanest.
3. Check dark scenes. Move a dark object on a mid-grey or dark background, where VA and some IPS panels smear.
4. Scroll a web page with small text. Smooth, readable text suggests good motion handling.
5. Move the mouse pointer quickly across the screen and watch for a trail.
6. Try a fast game or video, if possible.
7. Compare with another monitor side by side with the same test.

Your eyes are the final judge. A monitor that looks clean to you is a good monitor for you.

What response time do you need? By use

Office work, documents and spreadsheets

Nearly any modern monitor is fast enough. Pixel speed rarely matters for text. Prioritise comfort, ergonomics, brightness, viewing angles and connectivity. Models in our range, such as the Dell P2425H and the HP Series 5 monitors, are designed for this, per their makers, and a 100 Hz refresh rate makes scrolling and the mouse feel smoother. We confirm the specifications per unit. See our monitors category and our home office setup guide.

Films and series

Films run at 24 frames per second and are not limited by pixel speed. A decent panel is fine. Contrast, colour and HDR matter more. See our HDR, HDR10 and Dolby Vision explained article.

Casual gaming

A 100 to 144 Hz monitor with sensible overdrive is a good fit. You will notice smoother motion without paying for extremes.

Competitive gaming

Look for a high refresh rate, well-tuned overdrive, low input lag and variable refresh rate support. Read independent measurements if you can. A genuine fast IPS, a good TN or an OLED fits here. The mouse and keyboard matter as well, see our mechanical keyboard guide.

Photo and video editing

Colour accuracy, gamut and uniformity come first. Response time is secondary. See our colour gamut explained article.

Education and presentations

Pixel speed does not matter. Brightness, resolution and connectivity matter.

Panel tuning: why the same number looks different

Two monitors that quote the same response time may use different panels, different overdrive tuning and different electronics. One may be tuned carefully across refresh rates. Another may have a fixed overdrive that looks fine at its maximum refresh rate and poor at lower ones. A monitor that has variable refresh rate may need an overdrive that changes with frame rate. Makers sometimes call this adaptive overdrive. Cheaper monitors often skip it.

Because of this, treat the response time figure as a rough indicator and not a ranking. When possible, look at tests that measure real transitions across the range of greys, listing average and slowest times, and the amount of overshoot.

The role of backlight strobing

Some gaming monitors offer a strobing mode with names such as ULMB, motion blur reduction or 1 ms MPRT. It flashes the backlight in sync with the refresh rate, reducing perceived blur considerably. The drawbacks:

• The screen gets dimmer.
• Some people see flicker and find it tiring.
• It often works only at fixed refresh rates and cannot be combined with variable refresh rate.
• It can introduce double images (crosstalk) if poorly tuned.

It is a niche feature for competitive players. Try it and see. Most users keep it off.

Variable refresh rate and response time

Variable refresh rate (VRR) lets the monitor change its refresh rate to match the frame rate, reducing tearing and stutter. It also changes the ideal overdrive. Good monitors adjust overdrive across the range. Poor ones may show more ghosting at low frame rates or overshoot at high ones. If you game, look for VRR support and for reviews that test the monitor with VRR on. Sync technologies from graphics-card makers need compatible hardware, so check your graphics card and cable. See our HDMI 2.1 explained article for the cable and port side.

Reading a response time claim: a worked example

Suppose a monitor box says "1 ms". Here is how to interpret it.

1. Which measure? If the box says "1 ms (GtG)", the maker is claiming a grey-to-grey time, but probably the fastest transition at the fastest overdrive. If it says "1 ms (MPRT)", it describes a strobing mode.
2. At which overdrive level? If the 1 ms figure needs "Extreme" overdrive, check for overshoot at that level. If the clean "Normal" level gives 4 ms, that is the figure you will live with.
3. At which refresh rate? A claim measured at the top refresh rate may not hold at lower rates.
4. Typical or best? The best case is not the typical case.
5. What do independent tests say? Measurements of average and slowest transitions give the real picture.

Now compare with an office monitor quoting "5 ms". If its overdrive is well tuned and the refresh rate is 100 Hz (10 ms frames), 5 ms is perfectly adequate, and in real use it may look as clean as the "1 ms" monitor on a clean setting. This is why we encourage you to look at motion on the screen, not just the box.

Response time and HDR, colour and brightness

Fast response is only one part of picture quality. A monitor that excels at motion may have mediocre contrast or colour. Contrast, brightness and colour accuracy matter for films and HDR, and viewing angles matter if several people look at the screen. Do not sacrifice an area you care about for a number you will not notice. A balanced IPS monitor is the safest choice for mixed use. Our IPS vs VA vs OLED explained article, colour gamut explained article and HDR explained article help you balance them.

Settings that help on any monitor

1. Run the native resolution and the highest refresh rate your computer and cable support. In Windows, check the advanced display settings, since monitors sometimes default to 60 Hz.
2. Use a good cable. A poor or old cable can force a lower rate. See our HDMI 2.1 explained article.
3. Pick a sensible overdrive level by testing.
4. Turn off unnecessary image enhancements, which can add lag.
5. Use game mode on TVs.
6. Enable variable refresh rate if your hardware supports it.
7. Update graphics drivers and monitor firmware where available.
8. Match the frame rate to the refresh rate by capping frames in games if you do not use variable refresh rate.
9. Take care with strobing modes. Use them only if they suit your eyes.

Why your monitor may look blurry even with a fast response time

If motion looks smeary on a monitor with a fast response claim, check these causes before blaming the screen:

• The refresh rate is stuck at 60 Hz in the operating system.
• The game's frame rate is low or uneven.
• Overdrive is set too low (smearing) or too high (halos).
• A weak cable or hub limits the signal. For instance, a USB-C hub that outputs 4K at 30 Hz, like the Anker hubs in our range, per Anker, will look choppy on a 4K monitor. See our best USB-C hub guide.
• Motion smoothing or other processing is on, on a TV used as a monitor.
• The panel type is slow in dark transitions.
• Text and the mouse pointer look blurry because the resolution is not native.

Fix the setting first. Buying a new monitor will not help if the problem is a cable or a setting.

Care and longevity

Monitors are durable, and response time does not usually change over their life, though backlights dim slowly over years. Keep the screen clean with a soft, slightly damp, lint-free cloth. Avoid pressing on the panel. Keep vents clear, and plug the monitor into surge protection, since power surges are common and can damage the electronics. A monitor on a stand or arm at the right height protects your neck. Keep the box and receipt for the warranty period.

Monitors versus TVs for gaming and fast content

Many people play games on a TV, and TVs have changed a lot. Modern TVs often have game modes with low input lag, and some support high refresh rates and variable refresh rate over HDMI 2.1. The differences from a monitor are usually size, pixel density and processing. A TV is larger and viewed from farther away, so pixels look smaller from the sofa. A monitor sits close, so any smear is more visible. A TV without game mode can add noticeable lag. If you play from a sofa, a TV in game mode is a good option. If you sit at a desk and play competitively, a monitor tuned for it is better. For size and distance, read our TV and monitor sizes vs viewing distance article.

Buying checklist for different budgets

Basic office monitor. Prioritise IPS, full HD, 100 Hz if available, comfortable stand, and connections you need (HDMI, USB hub). Response time is not a deciding factor.

Mid-range all-rounder. Look for IPS, 100 to 144 Hz, variable refresh rate and reasonable overdrive. A good option for work and casual play.

Enthusiast gaming. Look for high refresh rate, measured response, low input lag, variable refresh rate and a well-tuned overdrive. Your computer must keep up.

Creative work. Look for accuracy, gamut and uniformity first.

Tell us your budget and use on WhatsApp, and we will recommend what is worth paying for.

A quick glossary

Pixel. One tiny dot of the screen that can change colour.

GtG. Grey-to-grey transition time of a pixel.

MPRT. Moving picture response time, a perceived-blur measure often tied to backlight strobing.

Overdrive. A technique to speed up pixel transitions.

Overshoot. A halo caused by overdrive pushing a pixel past its target.

Refresh rate. How many times per second the screen updates.

Input lag. Total delay from an action to its result on screen.

VRR. Variable refresh rate, matching the screen to the frame rate.

Strobing. Flashing the backlight to reduce perceived blur.

Common myths about response time

"1 ms is always better than 5 ms." Not necessarily. The measurement method and tuning matter more.

"Response time determines how good a monitor is for games." It is one factor, with refresh rate, input lag and sync.

"OLED has no motion blur." It has near-instant pixels, but sample-and-hold blur remains at low refresh rates.

"Higher refresh rate fixes slow pixels." It makes slow pixels more obvious.

"A 1 ms monitor has no ghosting." Ghosting depends on the whole range of transitions.

"Office monitors are too slow for anything." For work and films they are fine.

"Overdrive on maximum is best." It can cause overshoot. Try the middle setting.

Common mistakes when buying

1. Buying on the response time number alone.
2. Ignoring panel type.
3. Paying for 240 Hz or 360 Hz without a computer that can drive such frame rates.
4. Using the maximum overdrive without checking for halos.
5. Using a TV for competitive gaming without game mode.
6. Confusing input lag with response time.
7. Ignoring cables and ports, then running the monitor at a lower refresh rate than it supports.
8. Skipping the receipt and warranty.

Example scenarios

These are illustrative scenarios, not customer records.

The accountant. They use a 100 Hz IPS monitor for spreadsheets. Response time is irrelevant to them. Comfort and clarity matter more.

The student who games on weekends. They want a smooth experience for casual games. A mid-range 100 to 144 Hz IPS monitor with sensible overdrive is enough. A "1 ms" claim adds little.

The competitive player. They need a high refresh rate, low input lag and clean motion. They read measured reviews and test overdrive modes rather than trusting the box.

The editor. They want accurate colour for photos. They choose an IPS monitor with good accuracy, and treat response time as secondary.

Questions to ask any seller before you pay

1. Is the response time GtG or MPRT? Typical or best case?
2. At which overdrive setting is that measured?
3. What is the panel type?
4. What is the native refresh rate, and over which ports?
5. Does the monitor support variable refresh rate?
6. What is the input lag, if known?
7. Can I see a motion test on it?
8. What warranty applies, including dead pixels?
9. Is the box sealed, and will I get a receipt?

How to spot a fake or misdescribed monitor

Response time claims are among the most inflated numbers in electronics. A monitor may be sold as "1 ms" when the claim is MPRT with strobing, or as "144 Hz" when it accepts that signal but displays less. Use these ten checks together.

1. Verify the model number and serial. They should match on the box, the back label and the on-screen menu, and be verifiable on the maker's website.
2. Read the maker's specification sheet for the exact response time, its type (GtG or MPRT) and the conditions.
3. Check the panel type against the claim.
4. Confirm the refresh rate in the settings. The option should appear and the screen should run stably over the port and resolution you plan to use.
5. Run a motion test. Look for trails and halos at the settings you will use.
6. Check the overdrive settings in the on-screen menu. A monitor with a real fast-response claim usually has them.
7. Check for dead pixels and uniformity problems with solid-colour screens.
8. Check the ports and cables to make sure the advertised refresh rate is available.
9. Check the packaging and seals. Re-taped or damaged boxes can mean a used or swapped unit.
10. Check the warranty, receipt and seller. A genuine seller has a shop address and clear terms. A price far below normal is a red flag.

If you are unsure, bring the monitor to New Alnoor Exhibition, Second Floor, Shop C7, Accra Road, and we will help you check it.

Why buy your monitor from City Gadgets Kenya

• Genuine products, checked before they reach you.
• A real shop at New Alnoor Exhibition, Second Floor, Shop C7, Accra Road, Nairobi CBD, opening from 9:00 AM.
• Same-day delivery in Nairobi and next-day delivery outside Nairobi.
• M-Pesa payment and clear receipts.
• Honest advice, including telling you when an office monitor is all you need.
• Cables, hubs and accessories in our accessories category.
• Support and repairs through our repair service.
• Trade-ins through our sell page.
• WhatsApp help on +254745575931.

Your response-time checklist

• I know my main use and how much motion clarity I need.
• I checked whether the response time is GtG or MPRT, and typical or best case.
• I considered panel type and overdrive, not just the number.
• My computer can drive the refresh rate I am paying for.
• I tested motion on the screen, or read measured reviews.
• I checked the model and claims for signs of misdescription.
• I have a receipt and know the warranty terms.

Frequently asked questions

What is monitor response time? How quickly a pixel changes colour, in milliseconds.

What is the difference between GtG and MPRT? GtG is pixel transition time between greys. MPRT describes perceived motion blur, often with backlight strobing.

Is 1 ms better than 5 ms? Not always. Tuning and measurement method matter.

Does response time matter for office work? Hardly.

What is overdrive? A technique that speeds up pixels, which can cause overshoot if set too high.

What is input lag? The delay between your action and the screen showing the result, separate from response time.

Is OLED faster than IPS? OLED pixels switch almost instantly.

Do I need 240 Hz? Only for competitive play, with hardware that can drive it.

How do I test response time? With motion tests, by trying overdrive modes and comparing with another monitor.

How do I know it is genuine? Use the ten checks above.

Can I pay by M-Pesa? Yes.

Where can I buy a monitor in Nairobi? At City Gadgets Kenya, Shop C7, Second Floor, New Alnoor Exhibition, Accra Road.

Need help choosing?

Message us on WhatsApp with how you use your screen, your computer and your budget, and we will recommend the right monitor.

Related reading: Refresh rate explained · IPS vs VA vs OLED explained · HDMI 2.1 explained · Colour gamut explained