Input Lag, Or Why Faster Isn't Always Better

mr_sifter writes "LCD monitor manufacturers have constantly pushed panel response times down with a technique called 'overdrive,' which increases the voltage to force the liquid crystals to change color states faster. Sadly, there are some side effects such as input lag and inverse ghosting associated with this — although the manufacturers themselves are very quiet about the subject. This feature (with video) looks at the problem in detail. The upshot is, you may want to test drive very carefully any display boasting low integer millisecond pixel response times."

Comments

Reason for input lag

[Rotaluclac]

The reason for input lag is that manufacturers want the on-screen image to quickly change without ghosting. Here, quickly means "in as few ms as possible", not "without delay". So if you see a change only two seconds later, but the change is instantaneous, that's considered good.

To achieve this, the display electronics must know what the next frames look like. So they buffer two or three frames, then adapt the overdrive on a per-pixel basis to the contents of the next few frames.

Pro: smoother video playing
Con: a delay of two or three frames

Rotaluclac