Stuttering/slugish feeling when FPS drops below FPS Cap G-sync

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.
biggydeen
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Stuttering/slugish feeling when FPS drops below FPS Cap G-sync

Post by biggydeen » 05 Aug 2021, 04:04

Hi,

I've got a problem with the smoothness in games once my FPS drops below my capped settings. When my fps drops below the cap, i expierence some sort of stuttering/slugish feeling despite running 130 fps+ with G-sync on.

First my specs:

5800x
3080ti
16gb 3200mhz cl14

Using the settings recommended by BB (gsync 101 guide) and optimized windows 10 for optimal settings possible. Also running core park, ISCL (timer resolution) and MSI afterburner for FPS capping and undervolting.

I know stuttering/slugish feeling can mean anything. I did some testing to recreate the problem and it seems like the same feeling when I turn g-sync off. For example:

When running Battlefield 1 without cap and g-sync i'm getting steady 200 fps but gameplay is not smooth. Same thing in Battlefield V. When I turn G-sync on and set the cap to 141 it runs butter smooth. Unless the FPS drops below the cap to 130 for example. Then I immediately notice it's not butter smooth anymore and some kind of stuttering/slugishnesh is introduced.

This is very noticable on the bigger maps. My system can hold 140 fps easy on smaller maps and everything runs butter smooth. But on larger maps, FPS sometimes drops to 125-130. And I immediately notice the smoothness is gone.

There should be no noticable difference in smoothness between 130 or 140 fps. But for some reason I instantly notice this and the butter smoothness is gone.

I have to note that this is no hardware problem. I have this problem for at least 2 years and completely changed all hardware (mobo,cpu,ram and gpu). The only thing I did not change is my monitor though. But that does not seem to be the problem.

Other things I tested:

- Turning g-sync verifyer (in NVCP) on to make sure g-sync is working
- To rule out any software issues, I reinstalled windows 10, only installed all basics without anything else. I did not install afterburner, corepark. ISCL etc. I only turned some things off in windows like background apps, game bar, game mode and some other stuff. Used FPS cap in NVCP
- On some other forums people noticed this is caused by the USB 3.0 connection connected to the case. I removed the USB 3.0 cable and HD audio cable.

Even with the completely fresh install I notice the same problem. Once fps drops below the cap, it's not smooth anymore. Although it seems to run a bit better on the fresh install but that might also be my imagination.

The only thing I can think about is that this problem is CPU related. Because either Battlefield one or Battlefield V always uses up to 100% cpu on some cores. These games are very heavy on CPU and frame drops must be related to the CPU because my GPU is on 60% usage max at all times. So could it be that this is somekind of CPU lag I'm experiencing? I did notice that CPU was at 100%

I also remember I had this exact same problem with COD warzone. This game also tanks 100% cpu all the time. Regardless of running 100+ fps it never seemed butter smooth.

I'm 100% sure I'm not imagining things. Now I start to wonder if the butter smoothess i'm expierincing when running a steady 140 FPS should be the same when framerate drops below the cap? Maybe my expectations are wrong. I was expecting butter smoothness for anything above 100+ fps with G-sync.

The only solution I can think about is setting the FPS cap at 0.1% lows so there are never any framedrops. But that is wasting alot of resources my system is capable off. And small drops in frames should not be noticable.

Any idea what is going on here? And are there people that are running Battlefield 1 or 5 having the same exp?

P.s. i only tested this in BF1 and BF V as i'm preparing for BF 2042. I do not have other games installed at this moment. But I do remember I had this exact same problem with my Intel system when running COD warzone (i5 9600k+2070S). Same thing, high FPS but not butter smooth. COD warzone is also a cpu hog running 100% cpu all the time.

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jorimt
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Re: Stuttering/slugish feeling when FPS drops below FPS Cap G-sync

Post by jorimt » 05 Aug 2021, 11:16

biggydeen wrote:
05 Aug 2021, 04:04
The only thing I can think about is that this problem is CPU related. Because either Battlefield one or Battlefield V always uses up to 100% cpu on some cores. These games are very heavy on CPU and frame drops must be related to the CPU because my GPU is on 60% usage max at all times. So could it be that this is somekind of CPU lag I'm experiencing? I did notice that CPU was at 100%

I also remember I had this exact same problem with COD warzone. This game also tanks 100% cpu all the time. Regardless of running 100+ fps it never seemed butter smooth.
Continuing our discussion from the G-SYNC 101 comments section, if the framerate drops below your 140 FPS limit due to 100% CPU usage, G-SYNC can't fix this, only avoiding maxed CPU usage will.

It sounds like you are CPU-limited in these situations, especially since your GPU usage isn't maxed. CPU-limitation will cause the frametime performance issues you are describing.
biggydeen wrote:
05 Aug 2021, 04:04
I'm 100% sure I'm not imagining things. Now I start to wonder if the butter smoothess i'm expierincing when running a steady 140 FPS should be the same when framerate drops below the cap? Maybe my expectations are wrong. I was expecting butter smoothness for anything above 100+ fps with G-sync.
Your expectations are indeed incorrect. Again, G-SYNC will only prevent V-SYNC stutter. It cannot prevent system-side stutter, it will merely reflect it. As such, this issue is not directly related to G-SYNC and will occur with or without it.

The reason you have "butter smoothness" when running a steady 140 FPS, is the because the limit is the framerate cap you set, which means your system has performance overhead, so there is no CPU or GPU limitation. However, when it drops below your 140 FPS limit, it means it is now instead limited by either your CPU or GPU capability.

If your system is GPU-limited, you will experience more input lag due to an increase in the pre-rendered frames in the render queue. If your system is CPU-limited, you will experience sporadic frametime performance, which will result in recurring stutter and/or micro-stutter.

In CPU-limited situations, you can 1) attempt to lower CPU-heavy graphical settings 2) increase the internal resolution (downsample) to force the GPU to work harder and take the strain off the CPU and/or 3) upgrade your CPU and/or enable multi-threading (if your current CPU supports it and you haven't enabled it already, that is).
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teo
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Re: Stuttering/slugish feeling when FPS drops below FPS Cap G-sync

Post by teo » 05 Aug 2021, 16:39

What graphics API are you using? From memory, when I used DX11 in bf1/v my gpu usage would nearly always stay below max even when I wasn’t at my FPS cap. When I turned on DX12, my average FPS would go through the roof and my gpu would sit at 100% utilization—but there were noticeable hitches. Maybe trying testing if that makes a difference

biggydeen
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Re: Stuttering/slugish feeling when FPS drops below FPS Cap G-sync

Post by biggydeen » 08 Aug 2021, 06:08

I did some testing and saw some weird results. It does not seem to be related to my system not getting stable FPS. My FPS always seem to drop 1 fps below the cap multiple times. For example:

Running battlefield 1 at a certain map my FPS was steady around 135-140. It was overall pretty smooth but I noticed some stutter/lag when FPS drops. I never saw FPS drop (using the ingame perfoverlay) drop below 135. So I changed RTSS to cap at 120 FPS. Suddenly, I'm seeing FPS drops to <120... While before it did not even get under 130. Performance wise 120 fps cap and 140 fps felt exactly the same.

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jorimt
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Re: Stuttering/slugish feeling when FPS drops below FPS Cap G-sync

Post by jorimt » 08 Aug 2021, 09:57

biggydeen wrote:
08 Aug 2021, 06:08
I did some testing and saw some weird results. It does not seem to be related to my system not getting stable FPS. My FPS always seem to drop 1 fps below the cap multiple times. For example:

Running battlefield 1 at a certain map my FPS was steady around 135-140. It was overall pretty smooth but I noticed some stutter/lag when FPS drops. I never saw FPS drop (using the ingame perfoverlay) drop below 135. So I changed RTSS to cap at 120 FPS. Suddenly, I'm seeing FPS drops to <120... While before it did not even get under 130. Performance wise 120 fps cap and 140 fps felt exactly the same.
Those results aren't particularly weird. That sounds like frametime spikes to me, especially since it's only occasional.

When these occur, the framerate effectively drops to 0 and back as the affected frame takes longer than a single refresh cycle to render, causing the previous to frame to repeat as it waits for the next, creating stutter. These typically occur due to background asset loading during HDD/SSD access, but can have a variety of other causes. Regardless, such occurrences are expected, and can't always be eliminated.

As for why they still happen when you cap at 120, again, they effectively drop the framerate to 0 momentarily each time, so you could cap the framerate to, say, 30, and still might experience the same drop in these instances.
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biggydeen
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Re: Stuttering/slugish feeling when FPS drops below FPS Cap G-sync

Post by biggydeen » 08 Aug 2021, 14:00

jorimt wrote:
08 Aug 2021, 09:57
biggydeen wrote:
08 Aug 2021, 06:08
I did some testing and saw some weird results. It does not seem to be related to my system not getting stable FPS. My FPS always seem to drop 1 fps below the cap multiple times. For example:

Running battlefield 1 at a certain map my FPS was steady around 135-140. It was overall pretty smooth but I noticed some stutter/lag when FPS drops. I never saw FPS drop (using the ingame perfoverlay) drop below 135. So I changed RTSS to cap at 120 FPS. Suddenly, I'm seeing FPS drops to <120... While before it did not even get under 130. Performance wise 120 fps cap and 140 fps felt exactly the same.
Those results aren't particularly weird. That sounds like frametime spikes to me, especially since it's only occasional.
I did some more testing and checking frametimes. When the FPS is steady, the frametime is just one flat line with always the same frametime in ms (as expected). When FPS drops below cap, i can see it on the frametime line as a small blip but nothing big. Although I still notice it instantly as a hickup/stutter/unsmoothness.

Now I think I finally understand why. And you already have said it once but I saw some other YT video basically saying the exact same thing and it just hit me. Everytime the monitor is not receiving a steady pace of frames (due to bottlenecks somewhere) you will notice it as (micro)stutter. There is no way to fix this either with g-sync or any other solution. The only way to provide a steady pace of frames is by solving the bottleneck:

- Upgrading CPU/GPU (not possible in my setup) or overclocking
- Lowering graphical settings
- Lowering FPS Cap to 1% low or 0.1% low
- SSD instead of HDD
- System tweaks like using XMP profiles, Win10 optimal settings etc.
- Etc

The only way to have that buttersmooth gaming experience is by sending the monitor frames in exact the same pace every second.

I was expecting g-sync would fix all stutter and other things that are not smooth. But now it does make sense that it can never be buttersmooth if the rate of frames provided by the system is not steady. Maybe i'm just very sensitive to this. But it also might be the game engine because I do not notice it in all games.

I also had this problem on my older system when I had a 60hz screen. 60FPS was always buttersmooth but just dropping 1 fps below was causing stutter (due to v-sync was out of the sync of 60hz but also because frametimes were not consistent). This happend to litterally every system I had, g-sync, no g-sync, Intel, AMD, it does not matter at all. I have always noticed this and now I finally know why.

Can you confirm this?

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Re: Stuttering/slugish feeling when FPS drops below FPS Cap G-sync

Post by Chief Blur Buster » 08 Aug 2021, 14:38

Have you tried these:

- G-SYNC + VSYNC ON in NVIDIA Control Panel
- VSYNC OFF within the game settings

Some engines switch to a better algorithm that behaves better with VRR that way when you use this opposing setting combo.

Also, a higher-Hz monitor can help low-framerate stutter significantly because LFC penalty is much, much, much lower at high-Hz. LFC stutter is a 0.5/MaxHz error margin, so increasing MaxHz as much as possible helps reduce your LFC-derived stutter massively. In addition, 240Hz VRR makes everything less laggy because even 50fps frames are still delivered and refreshed in 1/240sec, reducing the VRR latency penalty (relative to ultra high frame rate VSYNC OFF).

VRR is the world's lowest-lag "non-VSYNC-OFF" technology, and ideally you want a frame rate range completely within your VRR range to get consistent lagfeel. So if your framerates gyrate above/below 141fps, you can still have lagfeel variances despite a cap (the cap helps reduce the differential lagfeel massively, but not completely), so having a VRR refresh rate range much wider than frame rate range, makes VRR much more pleasant to use in many games, in a low-lagfeel way, as well as an anti-LFC-stutter way.

Now that being said, engine & disk load stutter won't destutter, but smooth framerate variations will be stutterfree (ala www.testufo.com/vrr ...) so VRR will reduce a lot of stutter, but not all of it.
biggydeen wrote:
08 Aug 2021, 14:00
The only way to have that buttersmooth gaming experience is by sending the monitor frames in exact the same pace every second.
Not absolutely critical for minor realtime variances --

Internally, a game engine uses microsecond/floating point timestamps called "gametime", which determines the real world positions of all motion for a specific rendered frame.

Variable frame rates can look smooth if the timestamps of gametime is in perfect relative-sync with photon time (refreshing time).

Games that smoothly vary frame rates can have a gametime varying in relative sync with refreshing time, and you won't see stutter easily. But if gametime jitters badly relative to refreshtime, this type of stutter will punch through.

This is also why I recommend using VSYNC OFF in-game-settings (while using VSYNC ON in the NVIDIA Control Panel), it allows the gametime in an engine to float amorphously and be more likely in sync with photontime. Different games switch to different gametime algorithms depending on certain behaviors and it can be rather annoying.
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Re: Stuttering/slugish feeling when FPS drops below FPS Cap G-sync

Post by jorimt » 08 Aug 2021, 17:23

biggydeen wrote:
08 Aug 2021, 14:00
Can you confirm this?
I can confirm frametimes spikes aren't 100% avoidable in every game, sometimes even regardless of the system's capabilities. I.E. even brute force specs and optimal settings don't always solve it; the bottleneck can often lie in the engine itself.

It's a case-by-case issue. I personally do the most I can on the system specs and user settings-side to minimize them, and then ignore the remainder, knowing they can't always be fully eliminated.
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Re: Stuttering/slugish feeling when FPS drops below FPS Cap G-sync

Post by biggydeen » 09 Aug 2021, 03:44

Chief Blur Buster wrote:
08 Aug 2021, 14:38
Have you tried these:

- G-SYNC + VSYNC ON in NVIDIA Control Panel
- VSYNC OFF within the game settings

Some engines switch to a better algorithm that behaves better with VRR that way when you use this opposing setting combo.

Also, a higher-Hz monitor can help low-framerate stutter significantly because LFC penalty is much, much, much lower at high-Hz. LFC stutter is a 0.5/MaxHz error margin, so increasing MaxHz as much as possible helps reduce your LFC-derived stutter massively. In addition, 240Hz VRR makes everything less laggy because even 50fps frames are still delivered and refreshed in 1/240sec, reducing the VRR latency penalty (relative to ultra high frame rate VSYNC OFF).
Im currently running:

- G-SYNC + VSYNC ON in NVIDIA Control Panel
- VSYNC OFF within the game settings
- LLM on
- RTSS cap 130
- Core park on
- ISLC on (cleaning standby mem and timer resolution)
- MSI afterburner

Now battlefield games in particular also have settings like GPU restriction on/off and future frame rendering. I've set both to on.

I could opt for a higher HZ screen but to ultilize that I would have to lower graphical settings by alot. I'm one of those guys running high fps with high fidelity settings. I can't play games with low settings, just looks awfull.

So I was thinking with an 5800x and 3080ti I must be able to get that steady 140 fps in most games with high-ultra settings. And most of the times this is the case only in Battlefield games I instantly notice stutter when the FPS is not steady.

Maybe it's just the frostbite engine + heavy CPU load. Battlefield games are very CPU heavy and do not utilize the GPU that much. My 3080ti is sitting at 50% usage max but some CPU cores are running 100% all the time.

Maybe you got any recommendations of games to test any further? I got the xbox game pass ultimate.
jorimt wrote:
08 Aug 2021, 17:23
biggydeen wrote:
08 Aug 2021, 14:00
Can you confirm this?
I can confirm frametimes spikes aren't 100% avoidable in every game, sometimes even regardless of the system's capabilities. I.E. even brute force specs and optimal settings don't always solve it; the bottleneck can often lie in the engine itself.

It's a case-by-case issue. I personally do the most I can on the system specs and user settings-side to minimize them, and then ignore the remainder, knowing they can't always be fully eliminated.
I understand what you mean. I'm not sure this are frametime spikes i'm experiencing, it's not like a huge spike in the frametime line just a small blip. I also noticed this never happens on smaller maps. Gameplay is buttersmooth whole match. And playing with the FPS cap seems to do the trick. If the cap is low enough, the frametime line will be just a flat line and I never see any stuttering.

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Re: Stuttering/slugish feeling when FPS drops below FPS Cap G-sync

Post by jorimt » 09 Aug 2021, 08:35

biggydeen wrote:
09 Aug 2021, 03:44
So I was thinking with an 5800x and 3080ti I must be able to get that steady 140 fps in most games with high-ultra settings. And most of the times this is the case only in Battlefield games I instantly notice stutter when the FPS is not steady.

Maybe it's just the frostbite engine + heavy CPU load. Battlefield games are very CPU heavy and do not utilize the GPU that much. My 3080ti is sitting at 50% usage max but some CPU cores are running 100% all the time.
Part of the reason you're seeing CPU-limitation with a 3080ti is because you're only running the game at 2560x1440, and the 3080 Ti is more suited to a 4k resolution. Basically, in certain games, your resolution may be preventing your system from taking full advantage of the GPU's power.

Have you tried increasing the "Resolution Scale" above 100% in the Battlefield advanced video options? It should take some of the strain off the CPU and make the GPU work harder, potentially lowering the CPU usage and increasing the GPU usage in those scenarios.
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