analog vs digital signal synchronization and input lag

Everything about latency. Tips, testing methods, mouse lag, display lag, game engine lag, network lag, whole input lag chain, VSYNC OFF vs VSYNC ON, and more! Input Lag Articles on Blur Busters.
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flood
Posts: 929
Joined: 21 Dec 2013, 01:25

analog vs digital signal synchronization and input lag

Post by flood » 13 Jun 2014, 15:20

http://www.prad.de/en/monitore/specials ... art17.html

long and technical article, but basically it finds that the vblank signals in the analog and digital outputs are not synchronized on most graphics cards; hence measuring the input lag difference between a crt monitor and an lcd monitor with the lcd monitor connected to a digital output isn't a great idea.

what I'm curious about is whether this is significant input lag in the digital-to-analog process in the graphics card. If there is, then CRT monitors may have more input lag overall than some lcd monitors.

Q83Ia7ta
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Joined: 18 Dec 2013, 09:29

Re: analog vs digital signal synchronization and input lag

Post by Q83Ia7ta » 13 Jun 2014, 21:46

flood wrote:http://www.prad.de/en/monitore/specials ... art17.html

long and technical article, but basically it finds that the vblank signals in the analog and digital outputs are not synchronized on most graphics cards; hence measuring the input lag difference between a crt monitor and an lcd monitor with the lcd monitor connected to a digital output isn't a great idea.

what I'm curious about is whether this is significant input lag in the digital-to-analog process in the graphics card. If there is, then CRT monitors may have more input lag overall than some lcd monitors.
I can tell only from my experience playing QuakeWorld at 1155fps or Quake Live at 250fps at CRT@144hz and LCD@144hz. CRT feels a bit responsible but that difference is tiny. May it's placebo caused by motion blur at LCD@144hz.

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Chief Blur Buster
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Re: analog vs digital signal synchronization and input lag

Post by Chief Blur Buster » 13 Jun 2014, 23:13

Q83Ia7ta wrote:May it's placebo caused by motion blur at LCD@144hz.
LCD motion blur can actually adds an input lag sensation during eye-tracking situations (e.g. tracking eyes on moving objects, like www.testufo.com ...) The trailing blurring effect is a a visual form of lagging.

However, during stationary eye situations (e.g. staring at crosshairs), the strobing benefits aren't seen, and the absolute input lag matters a whole deal more.
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