When using testers like Leo Bodnar’s Lag Tester

[spacediver]

I think (hard to tell due to the writing style) the OP is asking about the fluctuations in readings due to variation in the time that the device sends a video signal relative to the current phase of the display's refresh cycle.

Not sure how the leo bodnar device handles this, but one solution is to take several readings. You'll end up with a (uniform) distribution of "lag times", ranging from 0+input lag to 1/framerate+input lag.

[Q83Ia7ta]

He calibrated devices somehow. It's monitor problem if it delays frame.
But this devices only supports HDMI and that's why only 1920x1080@60Hz. It's kinda useless for 144Hz monitors that support 144Hz by DVI or DisplayPort.

[l337g0g0]

ok now that were on point.

Yes so the device sends the video signal, does it over ride the monitors own 60 hertz?
This is the question.
Cause it if does not interrupt the monitors 60 hertz then the device sends a video signal and it might be in the middle of the monitors normal/default hertz?

So then you can reread my questions that add to this.

thank BTW...

[l337g0g0]

Yea i didn't read this page when i responded the first time.

Yea space driver nailed it.

and to add to that space driver you stated they do multiple times and i guess they take the lowest one as that would be the one without frame delay.

But let me add this question.
If a 60 FPS frame takes 16ms to display how can this device register anything under that since any frame to notify the device of it's video signal will ultimately have to wait 16ms.

It's puzzling to figure out how the device sends a video signal for it to read off the monitor faster than 16ms on the 60FPS monitor?

[Falkentyne]

Doesn't the state of vsync affect this?

Yes if you're running at 60hz refresh rate and vsync is on, the lowest input lag you can have is 16.7 ms.
But if vsync is OFF and the refresh rate is 60 hz but the framerate is much higher (e.g. 150 fps) this changes everything right?

[spacediver]

Sorry, yes I meant 1/framerate. Am editing my post now.

[l337g0g0]

@falkentype both wouldn't, cause a 60 FPS monitor is 60 FPS whether V sync is on or not.
Plus even if you use a 144 hertz, which they didn't but that's still 6ms or 7ms.

Point is the monitors tested so that the input lag at the top of the monitor is registering "3ms", 60 fps is 16ms, 120 is like 12ms and 144 is like 6 or 7ms.
Again how can the device receive a video signal of 3ms when the monitors 12ms?