How to Use the Latency Test
- Launch the test above and press F for fullscreen.
- Watch the cursor chase a target — the gap between the cursor and its target represents your total system display latency.
- A smaller gap = lower latency. The test provides a visual approximation of display lag by measuring the timing between frame requests and rendered output.
- Note: this measures total system latency — it includes GPU processing time, display pipeline delay, and the monitor's own input lag. It is a relative indicator, not a precise instrument measurement.
For the most accurate results, close other applications and background processes. GPU load affects the result as much as the display does.
Input Lag vs Response Time — The Critical Distinction
These two specifications are frequently confused, even in monitor reviews:
Input lag is the delay between a user action (mouse click, key press, controller input) and the corresponding visual result appearing on screen. It is measured in milliseconds. It encompasses the display pipeline: GPU processing + signal transmission + display processing + panel draw time. Input lag is what determines how "snappy" or "sluggish" a display feels.
Response time (GtG) is how fast a pixel switches from one color to another. It determines ghosting — the smear trailing behind moving objects. Response time has no direct relationship to input lag.
A monitor can have 0.5ms GtG and 30ms input lag (excellent motion clarity, sluggish feel). A monitor can have 8ms GtG and 4ms input lag (minor ghosting, very responsive feel). These are independent specifications measured in different ways.
The ghosting test above measures the practical effect of response time. The latency test measures the practical effect of input lag.
What Input Lag Numbers Mean for Gaming
| Input Lag | Gaming Suitability |
|---|---|
| Under 3ms | Imperceptible; excellent for competitive play |
| 3–5ms | Excellent; recommended for competitive gaming |
| 5–10ms | Good; suitable for most gaming including competitive |
| 10–20ms | Perceptible in fast-paced games; acceptable for casual play |
| Over 20ms | Noticeable delay; avoid for competitive or action games |
Most modern gaming monitors with Game Mode enabled measure 3–10ms input lag. Consumer TVs used as monitors often measure 15–40ms, which is why "Game Mode" on TVs exists — it reduces processing and can bring TV input lag to competitive monitor levels.
What Affects Input Lag
Game Mode / Low Latency Mode: The most impactful setting. Disabling post-processing pipelines (image enhancement, edge sharpening, motion smoothing) removes 5–20ms of added delay. Always enable Game Mode for gaming.
Refresh rate: Higher refresh rates reduce the maximum display lag. At 60Hz, a frame can sit in the pipeline for up to 16.7ms before display. At 144Hz, that maximum drops to 6.9ms. Higher Hz = lower maximum input lag.
Variable refresh rate (G-Sync / FreeSync): Adds approximately 1–2ms of latency on average in exchange for eliminating screen tearing. The trade-off is widely considered worthwhile.
Display resolution: Higher resolutions increase GPU rendering time, affecting total system latency — but this is GPU-side, not monitor-side.
Connection type: DisplayPort and HDMI 2.1 have negligible latency difference for gaming. Wireless adapters (some TVs) can add 5–20ms.
Frequently Asked Questions
What is monitor input lag?
Input lag is the total delay between a user action and its visual result on screen. It includes GPU processing time, signal transmission, display processing pipeline, and the time for pixels to physically draw the frame. A low input lag display feels immediately responsive to inputs; a high input lag display feels sluggish.
Input lag vs response time — what's the difference?
Response time (GtG) measures pixel switching speed — it determines ghosting and trailing behind moving objects. Input lag measures the total delay between action and visual result — it determines how responsive the display feels. They are independent specifications. A monitor can excel at one while performing poorly at the other.
How do I reduce input lag on my monitor?
Enable Game Mode or Low Latency Mode in the monitor's OSD — this is the most significant improvement available. Increase refresh rate if possible (higher Hz = lower maximum frame latency). Disable all image enhancement features (motion smoothing, edge enhancement, noise reduction) as these add processing delay.
Does game mode reduce input lag?
Yes, substantially on most displays. Game Mode disables post-processing pipelines that add 5–20ms of delay. On TVs used as monitors, enabling Game Mode can reduce input lag from 30–50ms to 5–15ms — a transformative difference. On dedicated gaming monitors, Game Mode provides a smaller but still worthwhile improvement.