What is Response Time

A quick pixel response time speed is needed to eliminate ghosting (trailing) behind fast-moving objects in fast-paced games.Just how fast the response time speed needs to be depends on the monitor’s maximum refresh rate.

A 60Hz monitor, for instance, refreshes the image 60 times per second (16.67 milliseconds in-between refreshes).So, if a pixel takes longer than 16.67ms to change from one color to another on a 60Hz display, you will notice ghosting behind fast-moving objects.

For a 144Hz monitor, response time needs to be lower than 6.94ms, for a 240Hz monitor, lower than 4.16ms, etc.Pixels take longer to change from black to white than vice versa, so even if all white to black pixel transitions are below the quoted 4ms on a 144Hz monitor, for instance, some dark to light pixel transitions still might take over 10ms.Consequently, you would get noticeable black smearing in fast-paced scenes with a lot of dark pixels involved, while in other scenes, ghosting wouldn’t be as noticeable.Generally, if you want to avoid ghosting, you should look for gaming monitors with a specified response time speed of 1ms GtG (Gray to Gray) – or lower.This, however, won’t guarantee flawless response time performance, which needs to be properly optimized via the monitor’s overdrive implementation.

A good overdrive implementation will ensure that the pixels change fast enough, but it will also prevent inverse ghosting (i.e. pixel overshoot).Inverse ghosting is characterized as a bright trail following moving objects, which is caused by pixels being pushed too hard via an aggressive overdrive setting.To find out just how well the overdrive is implemented on a monitor, as well as what setting should be used at which refresh rate, you will need to look for detailed monitor reviews.