old pc had no gsync brightness fluctuation, new pc has

Talk about NVIDIA G-SYNC, a variable refresh rate (VRR) technology. G-SYNC eliminates stutters, tearing, and reduces input lag. List of G-SYNC Monitors.
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Re: old pc had no gsync brightness fluctuation, new pc has

Post by Chief Blur Buster » 28 Mar 2021, 17:20

teG wrote:
28 Mar 2021, 11:49
Now that is very stange to me. Even stranger is the fact that cities skylines will show now sign of brightness fluctuation what so ever, which ever settings I throw at it, the only setting that causes the gsync to fluctuate brightness in this game is to set gsync to fullscreen and windowed mode rather than fullscreen mode.
I must remind everyone that this is a framerate-powered brightness fluctuation. The brightness of specific framerates-changes can be sometimes different. Different GPUs will give different frame rates.

The best way to debug GSYNC brightness fluctuations is to display a framerate indicator, such as from RTSS. Although these are average frame rates (trailing 1 second averages), you can corroborate brightness fluctuations with frametime spikes in the real time RTSS graph.

FSE/FSO/Borderless/windowed will often show different RTSS graph data, which can also help debug all kinds of framerate-powered artifacts. For example, one mode may have a much smaller frametime spike than a different mode (bigger spike = bigger brightness fluctuation), since sync technology & screen mode can influence the size of some frametime spikes, especially for bringing up a menu / dismissing a menu.

The FSE/FSO/Borderless/windowed/GPU/OS/upgrade is simply a cause-and-effect -- as often modifies the framerates/frametimes/spikes -- and thus the root cause of GSYNC/FreeSync brightness fluctuations, especially in imperfect implementations of LFC (Low Framerate Compensation algorithms) of VRR technologies.

It's possible on old PC, your framerates didn't change as dramatically, e.g. framerates only increased a bit. But with new PC, you have more dramatic difference between minimum framerate (throttled by disk, menu, OS, FSO quirks) & maximum frame rate (upgraded GPU). Bigger min-vs-max = bigger brightness fluctuation.

It is important to use the correct debugging tools, and understand that VRR brightness fluctuations is almost always framerate/frametime/spike-powered. Once oneself understands this, it becomes less confusing, and just an annoying display quirk. Though some of this can be mitigated somewhat by tweaking settings. Whatever tool you use (RTSS, MSI Afterburner, whatever), needs to show a framegraph overlay:

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Every time, I have ever done this, GSYNC flickering almost always corresponds with graph spikes. And graphs often look different FSO vs FSE vs Borderless. And framerate graphs look different between games. Not all GPUs have the same frame rate. Not all games have the same frame rate. Remember, all GSYNC flickering is framerate powered. Usually a situation where min-max is big (Unchanged minimum framerate + massively increased maximum frame rate).

When you upgrade a PC, some games don't improve framerate behavior smoothly (min-max sometimes becomes bigger.... minimum frame rate unchanged but maximum framerate increases). Other times it is Windows or the CPU that changes the min-max differential (aka bigger framerate swings = more flicker). So, if you understand GSYNC flicker becomes bigger for more spikey framerate graphs.

Perfect VRR should not have brightness fluctuations, but displays are never perfect...

Once this is understood better from the correct scientific perspective, things start to make better sense, even if a bit mildly annoying...
Everything in this thread makes sense to me, because I understand the cause of GSYNC brightness fluctuations. It's a frustrating display limitation that is amplified more on some systems than others.

Also, changing VRR range (easier on FreeSync monitors) can also reduce VRR flickering, e.g. setting min-Hz to 55Hz or 65Hz (as long as max-Hz is at least 2.5x+ min-Hz). But this is harder to do on G-SYNC native chipped displays -- they have more proprietary low frame rate compensation. So it is possible drivers can change the framerate behavior via changes to LFC or settings. Especially if a single NVInspector setting is different between old/new system, too (affecting the framerate spikes differently)...

Now, some settings (GSYNC+VSYNC OFF) changes the appearance of GSYNC flicker versus others (GSYNC+VSYNC ON), because VSYNC ON makes VRR behave slightly differently for frametimes faster than refresh cycles.

Have you ever done framerate graph debugging? If not, then you haven't even started any troubleshooting/debugging GSYNC flicker yet -- go do so now and see what findings you get.
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Re: old pc had no gsync brightness fluctuation, new pc has

Post by teG » 28 Mar 2021, 19:26

Thank you for your reply.

I do understand what causes the issue.

From the sounds of it. If I'm more sensitive to it then what ever gsync monitor I get I will most likely notice this issue in.

I might give the cru program a try but like we both kind of said it most likely won't help.

I still don't understand why in one game where the framerate jumps all over from 2fps to 40 fps to 144fps while loading a heavy scene where I can see that the game is also literally halting the screen that there is no sign of gsync fluctuation though.

One thing I've also noticed is that unplugging the monitor from the pc and plugging it in again while in a game (works in 2 out of 3 games so far) that the fluctuation stops. Until I quit the game and load the the game again.

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Re: old pc had no gsync brightness fluctuation, new pc has

Post by Chief Blur Buster » 28 Mar 2021, 19:51

teG wrote:
28 Mar 2021, 19:26
From the sounds of it. If I'm more sensitive to it then what ever gsync monitor I get I will most likely notice this issue in.
It varies from monitor to monitor too. The magnitude of the flicker can be fainter/nonexistent on some models and more dramatic on others, for the exact same specific software-induced framerate pattern.

So getting a new G-SYNC or FreeSync screen may affect things -- and may be better or may be worse.
teG wrote:
28 Mar 2021, 19:26
One thing I've also noticed is that unplugging the monitor from the pc and plugging it in again while in a game (works in 2 out of 3 games so far) that the fluctuation stops. Until I quit the game and load the the game again.
Interesting observation about the unplug-plug effect.

Sometimes, that has the effect of temporarily turning off GSYNC until you restart the game. Does GSYNC go "OFF" in the monitor's OSD menu when you unplug-plug in the middle of a game?
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Re: old pc had no gsync brightness fluctuation, new pc has

Post by teG » 28 Mar 2021, 21:20

I'll check and get back to you :)

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Re: old pc had no gsync brightness fluctuation, new pc has

Post by RealNC » 29 Mar 2021, 14:21

Some games only run in borderless windowed mode. Some others will run in fullscreen mode that is always using "optimizations", regardless of your compatibility settings, because the game itself has requested to run in that mode.
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Re: old pc had no gsync brightness fluctuation, new pc has

Post by teG » 29 Mar 2021, 18:53

I must admit that the things causing the brightness issues (bringing up an I game menu or loading a game) I find that the more I do it the less invasive the brightness fluctuation is after a while. Like the monitor gets used to it.

My settings are currently vsync on in game and off in nvcp but also with nvcp fps limiter capping frames at 100fps for certain games but I have a feeling that messing around with the vsync settings in game or in nvcp will make no difference.

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Re: old pc had no gsync brightness fluctuation, new pc has

Post by Chief Blur Buster » 30 Mar 2021, 00:32

TN panels are more prone to FreeSync/G-SYNC flicker than newer "Fast IPS" panels are too, so switching panel tech can help produce a more seamless VRR experience. It's something I've noticed.

TN was great for the fast GtG, but 2020-and-newer "Fast IPS" is rapidly catching up for motion quality purists. As long as you're OK with IPS glow, there are overall a lot fewer artifact issues with strobe/sync technologies (no more chessboard/lines inversion patterns / less or no more VRR flicker / smaller degradation during strobing / etc).
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Re: old pc had no gsync brightness fluctuation, new pc has

Post by teG » 30 Mar 2021, 03:07

Thanks again chief blur buster, this will be my last post on this thread as I have obsessed over this enough now. I appreciate your responses and your time.

I've messed around with my settings a bit more and I seem to have alleviated a lot of the issue. I turned off vsyn in game and on in nvcp and I turned off the frame limiter which I used in nvcp to cap my frames. Obviously when the frame rates get very low (25fps) and I load up menues in a game then there is very slight brightness fluctation but this is now the best outcome :)

If you take donatiosn for the site I would be more than happy to donate.

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Re: old pc had no gsync brightness fluctuation, new pc has

Post by Chief Blur Buster » 30 Mar 2021, 03:51

teG wrote:
30 Mar 2021, 03:07
If you take donatiosn for the site I would be more than happy to donate.
A Blur Busters Patreon is coming later this year -- keep tuned.

For now, you are free to the Blur Busters Amazon Affiliate Link (anything added to your Amazon cart via this link sends 2.5% of the value of cart to Blur Busters as a commission). Up to you of course, no obligation!
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Re: old pc had no gsync brightness fluctuation, new pc has

Post by teG » 08 Nov 2021, 17:36

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