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How do I eliminate frametime spikes from FPS drops (Gsync)

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.

How do I eliminate frametime spikes from FPS drops (Gsync)

Postby Wooohah » 10 Nov 2018, 07:37

Hoping you guys can help me with this. I've had an ASUS PG279Q for a while, but in many games I often times experience frametime spikes, most often from small FPS drops. Many of my games generally run smooth, but will experience the occasional frametime spike (some more frequent than others). What it visually looks like to me is a small hitch or a split second freeze and it just absolutely bothers the heck out of me.
Many of these frametime spikes generally happen when I for example turn around quickly and terrain has to load.

I originally switched over from just a normal 60hz monitor, and I have to say... I had the impression the gameplay was always smoother on that. I never remembered getting so many frametime spikes.

I've done a bit of reading on Gsync, but I'm still having some trouble understanding some of the technology. Isn't Gsync supposed to eliminate tearing and provide for a smoother gameplay experience?
Why would I be often times experiencing frametime spikes when the FPS goes from say... 130 to 110?

I run Gsync with Vsync on. I have tried Gsync with Vsync off, but I've noticed some screen tearing when I do that.

Any help is appreciated. I know my question might be a bit vague so feel free to ask me clarifying questions.
Specs:
-i7 6700k
GTX 1080
16GB ram
ASUS PG279Q
Samsung SSD
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Re: How do I eliminate frametime spikes from FPS drops (Gsyn

Postby jorimt » 10 Nov 2018, 13:16

Wooohah wrote:I originally switched over from just a normal 60hz monitor, and I have to say... I had the impression the gameplay was always smoother on that. I never remembered getting so many frametime spikes.

There's a simple reason, really: perceptual "contrast."

As in, 1. there's less of a contrast between 60 FPS and drops to sub 60 FPS (both for framerate drops and frametime spikes) at 60Hz compared to, say, 144 FPS and drops to sub 144 FPS at 144Hz (the higher the sustained framerate @higher max refresh rates, the more noticeable the drops), and 2. it's easier for most systems to sustain a 60 FPS target than it is for them to sustain 144 FPS or higher targets, which can create more framerate fluctuation, and thus, sometimes more (or at least more noticeable) frametime spikes.

Wooohah wrote:I run Gsync with Vsync on. I have tried Gsync with Vsync off, but I've noticed some screen tearing when I do that.

Yup, G-SYNC + V-SYNC "On" + system-side frametime spikes = stutter, while G-SYNC + V-SYNC "Off" + system-side frametime spikes = slightly less prolonged stutter AND tearing.

I answered your question in the other thread earlier as well:
https://forums.blurbusters.com/viewtopic.php?f=5&t=4042&start=10#p35774

Bottom-line, there is no real 100% fix for system-side stutter.
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Re: How do I eliminate frametime spikes from FPS drops (Gsyn

Postby RealNC » 10 Nov 2018, 17:57

G-Sync with vsync ON does seem to suffer from hitching while recovering from rendering freezes. I don't think there's a remedy. If a game has this "temporary tearing" issue with gsync + vsync OFF, using a different frame limiter sometimes helps. For some games, the in-game limiter has the issue, but RTSS does not. For some others, RTSS has this issue, but the in-game limiter does not.Trying other frame limiters too might help.
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Re: How do I eliminate frametime spikes from FPS drops (Gsyn

Postby Wooohah » 10 Nov 2018, 21:47

So essentially what I've been reading and what you guys have told me... a side effect of Gsync is frametime spikes. While my gameplay may be smoother overall, I may still run into frequent instances where I notice a slight split second freeze.

I honestly really kinda regret buying Gsync. I did my research before buying but I honestly never even came across the information contained in BlurBusters on how Gsync works and some issues until MONTHS after buying it (and experiencing issues).
Spent $800 on a monitor and even more for specs that can handle the monitor and I've been thoroughly disappointed.

I used to run an i5 6600k, 970 and a 1080p 60hz screen without Vsync. Never experienced tearing, very minimal frametime spikes or hitches. Now... playing trying the same game (BF4) constantly getting little hitches and "low FPS" warnings from when the FPS drops from like 142 to 120.

And @RealNC you're saying that using a different frame limiter may prevent the screen tearing in some games? I use RTSS and limit it to 142. If I set an in game frame limiter, will the in game frame limiter override the RTSS frame limiter?
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Re: How do I eliminate frametime spikes from FPS drops (Gsyn

Postby Wooohah » 10 Nov 2018, 21:50

Also, does Gsync actually work for windowed mode? I know many games have a "full screen" setting, but in reality are not really fullscreen games. For those games that are windowed mode, should I just have Gsync off? Should I have Vsync on? The only other monitor I have experience with is the 1080p 60hz monitor... it generally could always stay above 60 FPS so Vsync actually worked fine to smooth out some games. Would I be essentially experiencing 72 FPS on a 144hz monitor if I fall below 144 FPS?

Thanks in advance for answering my questions by the way
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Re: How do I eliminate frametime spikes from FPS drops (Gsyn

Postby jorimt » 10 Nov 2018, 22:47

Wooohah wrote:So essentially what I've been reading and what you guys have told me... a side effect of Gsync is frametime spikes. While my gameplay may be smoother overall, I may still run into frequent instances where I notice a slight split second freeze.

No, G-SYNC doesn't cause frametime spikes, period.

Those same frametime spikes happen with or without G-SYNC. It's just that G-SYNC + V-SYNC seems to have a slightly longer "recovery" period from the frametime spikes when directly compared to standalone V-SYNC or no sync. Regardless of the syncing method (or lack thereof) used, frametime spikes cause stutter, and the system is responsible for them, not the display.

But then standalone V-SYNC causes it's own form of stutter (which G-SYNC fixes), separate of frametime spikes (with FPS below the refresh rate) and/or increased input lag (with FPS above the refresh rate), and no sync obviously causes tearing (which again, G-SYNC fixes), whereas G-SYNC + V-SYNC causes neither of those.

That, and again, the smoother the overall experience, the more obvious the "slight split second freeze[s]" will be whenever they occur.

Wooohah wrote:Also, does Gsync actually work for windowed mode?

It does, but it's often spotty when compared to proper exclusive fullscreen mode.
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Re: How do I eliminate frametime spikes from FPS drops (Gsyn

Postby RealNC » 10 Nov 2018, 22:57

Wooohah wrote:And @RealNC you're saying that using a different frame limiter may prevent the screen tearing in some games? I use RTSS and limit it to 142. If I set an in game frame limiter, will the in game frame limiter override the RTSS frame limiter?

Can't you just disable the RTSS limit? Just enter 0 when using another limiter.

Wooohah wrote:Also, does Gsync actually work for windowed mode? I know many games have a "full screen" setting, but in reality are not really fullscreen games. For those games that are windowed mode, should I just have Gsync off? Should I have Vsync on?

I remember windowed mode gsync being good in the past, but with recent W10 versions it seems to be awful. At least for me. As soon as GPU gets to about 85-90%, the game will stutter.

Btw, "fullscreen" in some modern games, and also older ones where W10 redirects it, means borderless but with DWM disabled. G-Sync will work fine with that without having to enable windowed mode g-sync.

For games that truly use the old-style borderless mode, some can be forced to use fullscreen by using a command line option. Some Unity games for example can be started with "-window-mode exclusive".
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Re: How do I eliminate frametime spikes from FPS drops (Gsyn

Postby Wooohah » 12 Nov 2018, 03:45

Gotcha. So frametime spikes are caused by the system, having Gsync + Vsync enabled simply makes frametime spikes last longer due to the recovery speed being lower.

So i've read that if I have a 144hz monitor I should be setting my RTSS frame limiter to 142 and having Gsync and Vsync on. If I have Vsync off, I will have a faster "recovery" time between frametime spikes but I may get slight screen tearing on the bottom half of my screen.
Is a viable solution for me to overclock my monitor to 165hz, then limit my frames to 144FPS via RTSS, and run Gsync with Vsync off?
Will this cause any other side effects? For example if I fall below the Gsync threshold, I won't switch to Vsync, what happens?
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Re: How do I eliminate frametime spikes from FPS drops (Gsyn

Postby Wooohah » 12 Nov 2018, 03:49

I've been struggling with frametime spikes in many of my games, and I believe that's all started when I got this Gsync monitor.
In many games that run well, for example Warthunder or Battlefield 4, the game will be smooth, running at say... 140ish FPS. When I make a quick turn or something of that sort, it may drop to 100 or 110.
So far I've tried playing with Gsync On, Vsync off, FPS capped at 100. FPS drops and Frametime spikes are MUCH less common now. However I feel like I've lost the point of Gsync if I need to cap my FPS at a point that my system rarely drops under for games like that.
Is there any different solutions?
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Re: How do I eliminate frametime spikes from FPS drops (Gsyn

Postby Wooohah » 12 Nov 2018, 03:55

I'm sorry if my questions are a bit confusing, please ask me to clarify if you need to. I'm still trying to fully understand the relationship between Gsync and my Computer and how/ if I can "smooth" out my games a bit more.

I'm assuming both of you run Gsync monitors. Do you have games that run at your max capped FPS level? Do you get frametime spikes/ noticeable hitches when the FPS dips a bit? (For example, capped at 140, FPS dips to 100).

Is it technically "normal" for me to be experiencing some hitches/ split second freezes in games? (While the game itself generally runs smoothly)
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