G-Sync's 1ms Polling Rate: My Findings & Questions

Talk about NVIDIA G-SYNC, a variable refresh rate (VRR) technology. G-SYNC eliminates stutters, tearing, and reduces input lag.

Re: G-Sync's 1ms Polling Rate: My Findings & Questions

Postby jorimt » 13 Dec 2016, 16:46

Sparky wrote:
Haste wrote:btw jorimt, whats your take on that video from LinusTechTips that has almost 800K views.
https://www.youtube.com/watch?v=MzHxhjcE0eQ

His results are really weird.

Any idea what happened there?


What happened there is Linus is using a very tedious and time consuming method of testing, so it harmed the sample size(he had what, 4 samples per test?) He also didn't implement a proper control. (v-sync off, and a CRT as a comparison point on both GPUS, or at least SOME reference monitor that was tested on both systems). Then there's the question of how he controlled for framerate.

If you take the v-sync off 45fps results for example, Nvidia went 73 73 72 73 right? Looks super consistent right? Well no. That right there is proof the sample size is far too small, as at that framerate you get plus or minus 11ms just from the framerate alone.

Then there was the time they tried to test latency on the Steam Link: viewtopic.php?f=15&t=2831

Exactly, no control group whatsoever.

What they were aiming to test was input latency, and instead ended up recording the variances between the system and monitor configurations. AMD and Nvidia cards have very different frametime performance, for instance.

Pushing each system to its limit at 45 fps on Crysis 3 effectively meant when there was a frametime variance, each system had nowhere to go but down. They should have tested with CSGO or the like, so that they could have sustained far higher frames, and capped at the desired limit.

What many don't understand, is even with v-sync off at 300+ fps, there is often large input latency variations from shot to shot; one shot can have as high latency as double buffer v-sync, and the next could be nearly instant. It's the averages over dozens of samples that count, and you must have a control group or the results mean nothing.
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Re: G-Sync's 1ms Polling Rate: My Findings & Questions

Postby Haste » 13 Dec 2016, 19:41

Thanks for the answer guys.

This is quite sad when a video like that can misinform 800K viewers.
Meanwhile people doing genuine tests have a much smaller reach.
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Re: G-Sync's 1ms Polling Rate: My Findings & Questions

Postby RealNC » 13 Dec 2016, 20:37

I mentioned in the past that Linus doesn't actually know what he's doing. He has a marketing youtube channel and unboxing videos. He's not actually a tech guru or anything.

He should not ever be taken as some kind of authority. His channel is very fun to watch, but that's as far as it should go.
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Re: G-Sync's 1ms Polling Rate: My Findings & Questions

Postby lexlazootin » 14 Dec 2016, 05:34

Yea Linus can frustrating some times...

That FreeSync G-Sync video is a perfect example of bad tests.

Try and make sense of these two graphs showing steam link latency: https://youtu.be/mliW5zppm00?t=6m44s

They even try to fix it with the annotation on the video but it still don't make ANY sense.

And they went out of their ways to get a $1000 HDMI cable to call bullshit and they basically say "My word over theirs" and don't do any real testing...
https://www.youtube.com/watch?v=Zgy5fX-VPCs

ffs Linus.
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Re: G-Sync's 1ms Polling Rate: My Findings & Questions

Postby jorimt » 14 Dec 2016, 11:53

lexlazootin wrote:Yea Linus can frustrating some times...

That FreeSync G-Sync video is a perfect example of bad tests.

Try and make sense of these two graphs showing steam link latency: https://youtu.be/mliW5zppm00?t=6m44s

They even try to fix it with the annotation on the video but it still don't make ANY sense.

What was the "Client" and "Server" labeling all about?

Regarding the first "frames" chart, seeing as he's using a 240 fps phone camera, you'd multiply the total frames from click to reaction by the the frametime of a single video frame, which in this case would be roughly 4.2ms.

While he never specified what refresh rate, framerate, or settings he was playing at, and whether v-sync was on or off, if his numbers are to be believed, "Server" (I'm assuming this is his test directly on the PC) would be 54ms of input latency, and "Client" (which I assume is his test on the Steam Link) would be 100.8ms.

So no, not good at all, that's nearly double the input latency of playing locally.

I'm not even going to try and figure out his second chart.
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Re: G-Sync's 1ms Polling Rate: My Findings & Questions

Postby Sparky » 14 Dec 2016, 14:35

Sparky wrote:
Haste wrote:btw jorimt, whats your take on that video from LinusTechTips that has almost 800K views.
https://www.youtube.com/watch?v=MzHxhjcE0eQ

His results are really weird.

Any idea what happened there?


What happened there is Linus is using a very tedious and time consuming method of testing, so it harmed the sample size(he had what, 4 samples per test?) He also didn't implement a proper control. (v-sync off, and a CRT as a comparison point on both GPUS, or at least SOME reference monitor that was tested on both systems). Then there's the question of how he controlled for framerate.

If you take the v-sync off 45fps results for example, Nvidia went 73 73 72 73 right? Looks super consistent right? Well no. That right there is proof the sample size is far too small, as at that framerate you get plus or minus 11ms just from the framerate alone.

Then there was the time they tried to test latency on the Steam Link: viewtopic.php?f=15&t=2831


Here's the post I made on that topic in the other thread. Anyway, that error shouldn't have made it through a smell test.
It looks to me like whoever did the graph screwed up the calculation.


I'm assuming:
Client would be the input latency measurement of the monitor plugged into the steam link.
Server would be the machine the game is running on.
Frames on the first graph is number of video frames from their 240fps camera.


Now, 1/240 of a second is 4.16 milliseconds. That makes the 13 and 24 frames from the first graph translate to 54ms and 100ms respectively. For CS:GO that's ridiculously high(in both cases). Their milliseconds graph would require a framerate of 4166.6 to match up to the data in the previous graph.

Basically instead of dividing by .24(frames per millisecond), they multiplied by .24
Or they divided by 4.16 milliseconds per frame instead of multiplying. Whichever.
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Re: G-Sync's 1ms Polling Rate: My Findings & Questions

Postby jorimt » 15 Dec 2016, 22:30

Just a heads up, I posted preliminary input latency numbers in my OP on the other thread (research ongoing):
http://forums.blurbusters.com/viewtopic.php?f=5&t=3073
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Re: G-Sync's 1ms Polling Rate: My Findings & Questions

Postby flickerismotiontoo! » 11 Jan 2017, 17:20

My gtx 1070 & Acer x34a monitor give me sometimes nayghty flicker only on top of the screen. Thats weird..
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Re: G-Sync's 1ms Polling Rate: My Findings & Questions

Postby Chief Blur Buster » 11 Feb 2017, 21:36

flickerismotiontoo! wrote:My gtx 1070 & Acer x34a monitor give me sometimes nayghty flicker only on top of the screen. Thats weird..
If this happens to you again, do you have a video of this?
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Re: G-Sync's 1ms Polling Rate: My Findings & Questions

Postby mminedune » 18 Mar 2017, 07:50

So i ditched my 1080 SLI and first time I'm running single in years got 1080 Ti.
And i can say with 100% certainty Gsync does not work properly with SLI it causes weird tearing until you put vsync on and yes vsync is working with gsync in SLI. This was also the case when i ran 980 SLI.

I no longer get tearing on lower part of the screen like i did with SLI and im running all the way up to my 162fps cap. With SLI and vsync it was annoying and yes it causes latency and when SLI frame pacing is off it will cause stutter and hitching.

So yea if you want to enjoy gsync don't use SLI. Im now playing with gsync on vsync off and frame cap and gsync soo much better.
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