Input Lag vs. Cable Length

[masterkaj]

I know I am splitting hairs here, but what is the delay (probably in nanoseconds) between a 1.5' and a 15' DVI-D cable? Would it even be perceivable in an input lag test?

Example:
Two identical monitors set side by side running the input lag timer test(Found here: http://tft.vanity.dk/ ); one using a 3ft cord and the other using a 15ft cord.

 

[SonicIce]

my instinct says the extra 13.5 feet of cable length will account for less than 1ms of lag. but i would be curious to see it tested

a simple calculation says that it takes light .0000137 milliseconds to travel 13.5 ft D:. now i don't know about real world speeds in cables, though

 

[masterkaj]

my instinct says the extra 13.5 feet of cable length will account for less than 1ms of lag. but i would be curious to see it tested

a simple calculation says that it takes light .0000137 milliseconds to travel 13.5 ft D:. now i don't know about real world speeds in cables, though

Yeah, I wanted to test it; but I don't have a good camera to do it (I tried ). Was just curious today because I was setting up a new build for a friend and he likes having his monitor and mouse pad pretty far away from the desktop.

I'd like to see someone run a test with a short cable against a CRT. Then run that same test with the longer cable against the CRT. I'm doubting there will be any perceivable difference; but who knows.

 

[Athadeus]

According to this,
http://answers.yahoo.com/question/index?qid=20081125114015AA0EpoI

Propagation speed is affected by insulation, such that in an unshielded copper conductor it is about 96% of the speed of light, while in a typical coaxial cable it is about 66% of the speed of light.

Coax should be similar enough in shielding to compare to DVI-D.

Speed of light = 299,792,458 m/s
299,792,458 m/s * .66 = 197,863,022.28 m/s
197,863,022.28 m/s = 649,156,897 ft/s
12 ft / 649,156,897 ft/s = 1.848551568265938e-8 sec = 18.4855157 nanoseconds

1.54 ns / ft delay basically.

That would be the difference between a 3' and 15' cable. I don't think you'd be able to prove that there was a difference between a 1' and 100' cable with any sort of (non-specialized) monitor & camera test.

 

[videogames101]

Worry about signal degradation, not delay bro.

 

[Arcanedeath]

Over such short distances it's a non issue as long as it works at all.

 

[Martimus]

I know I am splitting hairs here, but what is the delay (probably in nanoseconds) between a 1.5' and a 15' DVI-D cable? Would it even be perceivable in an input lag test?

Example:
Two identical monitors set side by side running the input lag timer test(Found here: http://tft.vanity.dk/ ); one using a 3ft cord and the other using a 15ft cord.

The input lag difference would be inperceivable, the difference in signal interference and voltage drop between the two would be huge though.

What kinds of electronic devices are near the cable? Anything with large current flow will cause heavy interference in the signal (like an electric motor/compressor)