Answer:
Input lag (also called display lag) is the delay between your GPU sending a frame and the monitor actually displaying it on the screen.
This is an essential aspect of gaming. Ideally, the display lag should be lower than the refresh rate cycle of the display. For instance, less than 10ms on a 100Hz monitor.
Input lag (also referred to as display lag in monitor testing) is the delay, measured in milliseconds, between a command being sent from an input device such as a keyboard, controller, or mouse and the corresponding action appearing on the screen.
This also includes all the processing of the image, such as scaling/upconverting, HDR, frame interpolation, deinterlacing, etc.
As you might expect, the amount of input lag is vital for competitive gaming, where every millisecond counts.
However, neither TV nor monitor manufacturers state the input lag in the display specifications, which is why doing detailed research before getting a new display is highly recommended.
Input Lag vs. Response Time
Input lag should not be confused with response time speed. While input lag measures the delay between an input command and the image appearing on the screen, response time refers to how quickly pixels can transition between colors. Response time is typically specified for monitors, but not for TVs.
Response time is measured as the speed at which pixels change from one shade of grey to another, which occurs after the frame is processed.
Input Lag: TV vs. Monitor
Since TVs over-process the frames, they have higher input lag than monitors.
Many TVs thus offer a dedicated picture preset, usually called ‘Game Mode’, which bypasses certain image processing to decrease input lag.
When looking for a TV for console gaming, it’s of utmost importance to check whether it has this feature. Although some may be more sensitive to high input lag than others, lower is always better.
If you’re looking for a monitor for gaming, there’s usually nothing to worry about, as most high refresh rate gaming monitors have low input lag as well as a quick response time.
For non-gaming purposes, reasonably high input lag isn’t much of an issue since you won’t be able to notice it in everyday use.
How We Measure Input Lag
We use OSRTT (Open Source Response Time Tool) to measure total system input lag and then we separate display lag, which is the time it takes the monitor to take in a new frame, process it and start drawing it.
Below, you can see the results we got when measuring the total system input lag of the BenQ EX271UZ at 240Hz.
How To Reduce Input Lag
If you are experiencing high latency, then make sure to check the following items before blaming your TV or monitor:
- Check your network connection for ping
- Ensure that you’re in the TV’s Game Mode
- Check your monitor settings for ‘Low Input Lag’ or similar features
- Check if your controller is damaged or has bad batteries
- On some monitors, latency can be lower when Adaptive-Sync (VRR, FreeSync, G-SYNC) is enabled or disabled in the OSD menu
- Avoid cable adapters
- Favor controllers with cables instead of wireless for lower input lag overall
- Enable NVIDIA Reflex or AMD Anti-Lag features in settings if you have a compatible GPU and play a supported game
