Analog output has Higher latency on modern Graphics cards?

[Sparky]

since the CRT on the analog port seems faster, can that mean that the analog port on the gtx 980TI has not really slower latency than the digital one? or maybe the LED tested is just slower even with the advantage of supposed faster HDMI digital port? what you think?

We can't really tell with that test if there is more lag than there should be. Could be either the DAC is laggy, the LCD is laggy, neither, or both. Going by the photos I'm only confident the CRT is between 0ms and 40ms faster than the LCD, which isn't enough information to make a conclusion.

If you're using a high framerate v-sync off test(first reaction), a CRT should have an absolute latency <2ms, and a fast LCD can be <5ms. However a timer in the middle of the screen only measures the one point, so the measurement is heavily impacted by refresh rate.(so you need a lot more data to figure out how big the difference is between the two monitors)

It's like trying to figure out if runner A is slower than he used to be, but our only data points are what lap runner A and runner B are on at the moment.

[Chief Blur Buster]

since the CRT on the analog port seems faster, can that mean that the analog port on the gtx 980TI has not really slower latency than the digital one? or maybe the LED tested is just slower even with the advantage of supposed faster HDMI digital port? what you think?

MIrror lag can outweigh adaptor lag, or vice versa. It's unanswerable without some absolute tests or some form of lag calibration.

To calibrate your mirroring lag differential, you preferably need two identical displays connected to the same port type. Measure lag. Then swap cables. Measure lag. See if the lag follows the display or the lag follows the port (graphics card). This is not something you can do if you are unable to swap ports at the GPU end (keep using the same monitor inputs). Basically connecting your CRT to the HDMI port and the LCD to the VGA port. Since this is typically not possible (without introducing external adaptors), it's not possible to calibrate mirroring lag via the cable-swap technique.

e.g.
Display "A" output connected to GPU port "A".
Display "B" output connected to GPU port "B".
Measure lag

Display "A" output connected to GPU port "B".
Display "B" output connected to GPU port "A".
Measure lag

This can help determine mirroring lag, and allow you to calibrate for it by watching how the lag increases/decreases when you swap ports. But only if you can keep using the same output (only swapping ports only on the GPU side). This mirroring-lag calibration is GPU specific and system specific (performance related) unfortunately. So it will not be practical in your case to determine mirroring lag.

If lag differences of 2 displays exceed mirroring lag, then the display lag difference can overwhelm mirroring lag.

A better approach may be to use a splitter, but that is not always practical with a digital display and an analog display.

[3dfan]

thanks people for the clarification, advices, etc, my main purpose on this was to try to contribute on A solid lad user query on a GTX 980 TI analog port performance, so in some ways try to testify if its true that its analog ports had higher notable latency than its digital ones due to supposed manufacturer decision to priorize analog ports for projectors, and not on latency performance with the latest analog port cards, and since i have part of the hardware he mentioned, a GTX 980 TI and a CRT, unfortunatelly dont have a 144hz TN monitor, maybe my test would somewhat help, maybe not, didnt hurt me to try .
mirroring latency test or LCD vs CRT input lag has not been my purpose actually, but i appreciate related advice for future testings

A solid lad left me curious about what he read about older analog input being faster on older cars than modern ones, so, i rememberd i have an old functional MSI NX8600GT (nvidia geforce 8600 GT) a card from an era where analog signals were the norm, so surely it has to have optimized latency analog signals, it has 2 DVI I, 1 S-video ports.
i did some video test to compare on the CRT if its a notable analog latency differente with the 8600 GT and GTX 980 TI, at least by eye,
didnt have a game to test on both cards, so did a kind of "raw" test to see if there is a notable comparable inputlag by just pressing an moving mouse keyboard keys and buttons.

sorry for the quality on the videos, need more time to learn better how to properly setup light and camera exposures, shutter, apps, etc. and apply your suggestions

2 videos of GTX 980 TI and the FW900 CRT:
keyboard key input lag test:

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mouse motion and buttons input lag test

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now, 2 videos of 8600 GT and the FW900 CRT
keyboard key input lag test:

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mouse motion and buttons input lag test

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at least for me, there seems not to be a notable latency difference between the cards.

[A Solid lad]

Thank you very much for taking the time to perform these test 3dfan!
It was interesting to read thru what you wrote, and what other users had to say.

[3dfan]

i also have realized that using software interpolation while watching the videos locally in my pc, at slowest speeds, allow to better apreciate the time diference between the button - key pressing - moving and the reaction on the screen, for example i used "media player classic" video player software and set the video speed at 0.25 (the slowest it allowed me) and while interpolated, its slow motion movement looks very smooth, of course there will be artifacts due to the interpolation but what is important to see, is good apreciated. i found it usefull when a high fps camera is not available. of course not a pro way to measure, but to me fortunately as a GTX 980 TI analog user, dont see any appreciable differences between latency between both cards.

i occasionally competitively play fighting games on this setup and havent feel input lag issues.

[A Solid lad]

i also have realized that using software interpolation while watching the videos locally in my pc, at slowest speeds, allow to better apreciate the time diference between the button - key pressing - moving and the reaction on the screen, for example i used "media player classic" video player software and set the video speed at 0.25 (the slowest it allowed me) and while interpolated, its slow motion movement looks very smooth, of course there will be artifacts due to the interpolation but what is important to see, is good apreciated. i found it usefull when a high fps camera is not available. of course not a pro way to measure, but to me fortunately as a GTX 980 TI analog user, dont see any appreciable differences between latency between both cards.

i occasionally competitively play fighting games on this setup and havent feel input lag issues.

That's reassuring to know, in case I do decide to put my IBM p275 back into action.

[Chief Blur Buster]

3dfan, thank you for your fantastic addition to this thread!