Optoma GT760 Projector – Special Features

Lag Times

For those unfamiliar with the term, lag time is the offset difference between the actual “run-time” of the media player and when it actually processes through the projector and becomes an image on your screen. Although it is measured in the hundredths/thousandths of a second, it can be a big deal with home theater enthusiasts and a HUGE deal with gamers. Games require split-second action and if the offset is too significant, it’s really going to mess with your Chi not to mention help you expand the diversity of your profanity vocabulary. So here’s the breakdown; a lag time of around 35 milliseconds is the norm.

A measurement of 35 or less is best since the human brain generally cannot detect the difference at that speed. However, 50 milliseconds or higher is just too much difference; ergo, anything around 50 or higher is just not a great feature in the world of projectors.

The GT760 running our input lag test, produced variable results, and in some ways it’s interesting. Basically, I played with different modes, and Presentation, at least in some cases seems faster than Movie. I can’t explain that, but here’s what we found, after taking some 30 separate lag time images, due to the variation. The readings grouped neatly into 3 groups, which probably tells us some things about the projector.

• Two of the images taken showed 0 lag time.  (Both of those were taken in Presentation mode)
• Most of the rest of the images showed results of 14 to 17 ms.   (at least 20 images).
• But three of the images showed input lag times in the 33 – 35 ms range.

Of course, 35 ms is considered fast enough to satisfy almost all serious gamers, when playing their fastest games, but once we get below 20 ms, the word from gamers seems to be, further improvement doesn’t really mean anything. We consider 50ms the minimum acceptable to most serious gamers, but 35 ms, will tend to satisfy those who might have an issue with 50 ms. And that brings us to the variable results. It’s interesting that the times center around either 0, 17, or 34 seconds input lag. Now consider we’re running at 60fps. Basically our results fall neatly into:

• 0 frame delay (0 lag times)
• 1 frame delay (14-17 ms lag times)
• 2 frame delay (33-35 ms lag times)

After all, 1/60 of a second is 16.667 ms! So, the delays seem to be timed to the source signal.  Interesting, and I’m sure there’s a good engineering explanation, but let’s stay focused on gaming. I won’t guarantee this, but it seems like Presentation mode (with auto aspect ratio turned off), stays either at 0 or in the 17ms range, while Movie seemed to be 17 or 34 ms ranges.  That tells us that there’s some processing likely going on in Movie mode that’s costing a 1 frame delay, compared to Presentation. But no matter, if Presentation mode can keep you at 17 ms and under, you have a great gaming projector and even if it occasionally drops to 35ms, you still have a reasonably fast gaming projector! Bottom line, fast as you need it to be.