G-Sync requiring very low FPS cap?

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.
sekta
Posts: 16
Joined: 19 May 2015, 22:19

Re: G-Sync requiring very low FPS cap?

Post by sekta » 04 May 2017, 03:05

My experiences and results in Counter-Strike at 2560x1440 @ 165 Hz, Multicore Rendering enabled, Game Mode On (Off in Gamebar), High Performance Plan with the monitor's OSD Refresh Rate overlay enabled:

VSYNC OFF (Use 3D application setting, off ingame)
162 FPS RTSS = shudder/hitching, refresh rate at steady 162 with constant split second spikes down to 130/140 up to 164/165
162 FPS Ingame = shudder/hitching, refresh rate fluctuating wildly and hitting limit
162 FPS RTSS & Ingame = Extreme microstutter

VSYNC ON (Forced On in Nvidia Control Panel)
162 FPS RTSS = smooth but very consistent hitching, steady 162 with constant split second spikes down to 130/140 up to 164/165
162 FPS Ingame = smooth but very consistent hitching, refresh rate wildly fluctuating and hitting limit
162 FPS RTSS & Ingame = Same as just 162 ingame

Whenever it hit the limit, it wasn't always 165, it was mostly staying at 164. If left uncapped, the refresh rate would be mostly 164 with flickering to 165. So for input lag reduction, I think it would be best to have the spikes hit a maximum of 3 below the refresh rate.

The ingame limiter looks pretty bad compared to RTSS so I stopped using it and used RTSS only and dialed down the limit until the hitching stopped. At 165 Hz it became noticeable smoother once I hit <150 FPS, however there is still the constant split second refresh rate spikes down to the 130 region up to the 150 region every few seconds but it's no longer hitting the refresh rate limit and the hitching is much less noticeable.

I'm wasn't sure if this was because of the 165 Hz overclock on the monitor, since it is native 144 Hz and the GSYNC module may only work correctly to 144 Hz so I reduced the overclock. 160 Hz and 155 Hz both suffered from the split second refresh rate spikes. However 150 Hz worked perfect. No spiking at all. This was a relief because my monitor has the faulty firmware where at 144 Hz a strip of pixels in the center gets cut out and moved to the right side. I'm not sure if this is specifically my monitor that can't handle the overclock or if it is the GSYNC module.

So at 150 Hz, the fluctuation completely stopped. No shudder or hitching. At 147 FPS (RTSS) it remained stable with the refresh rate being 146/147/148. That is still too close to the limit for my tastes. With VSYNC OFF, the screen had noticeable tearing/artifacting at the very bottom while strafing back and forward past solid black and green. At 138 FPS this pretty much went away and I couldn't make it tear.

Using the ingame limiter too close to the RTSS limiter with VSYNC disabled made it microstutter pretty badly. I was thinking of having the CSGO limiter act as a low latency limiter and RTSS controls any upward spikes but it doesn't work when VSYNC is disabled. With VSYNC On, the microstutter is gone but the refresh rate fluctuates wildly still. Having VSYNC off revealed how bad it is to have the ingame limiter and RTSS limiter active at the same time. Does VSYNC fix it or just hide it? Not sure so I don't recommend doing it. Set the ingame limiter to the refresh rate maybe and leave it there. I know some games have bad input lag if you completely disable the ingame limiter.

Setting RTSS to cap at 146.5 FPS was better than 147 FPS limit. The refresh rate limit flickered constantly at 146/147 instead of 146/147/148. Reaching 2 FPS below the limit is cutting it close. 3.5 FPS cap below the refresh rate seemed good. Maybe a little lower if the ingame limiter interferes with it with VSYNC off. I disabled VSYNC to test the interference, with 146.5 RTSS limit, ingame fps_max 146 had extreme microstutter and went away at 148. I ended up just setting the ingame limiter to the refresh rate, 150 and saw no downsides. It's probably better to do this than to downright disable it as that can lead to problems with some games. Strafing and spinning rapidly the FPS/Hz did not budge from 145.

After reenabling VSYNC and opening the game again, I was once again getting the weird split second refresh rate spikes downward to 130 region every few seconds. I was also able to spin around and hit 150 Hz. Not sure if this is because of the Creators Update or if it is the gimmicky overclock function on these monitors. The game looked smooth though...without the overlay I wouldn't notice. Still really annoying how everything was working perfectly and then a restart ruins everything. Rebooted, tried VSYNC forced off and VSYNC forced on and was able to hit 150 Hz while spinning. When set to Use 3D application setting, I couldn't hit 150 Hz. Reenabled VSYNC and once again, couldn't hit 150 Hz and it was stable. VSYNC on I can't tell any difference in input lag and it hides any microstutter from RTSS/Ingame limiter collision and bottom screen tearing but at the same time it is a hit or miss whether the refresh rate is stable or not. Every time I set VSYNC to "Use 3D application settings" it is smooth and consistent. To finish up the settings to see if I could tweak it and make it any more consistent, I tried the FPS limit trick used for removing double buffer VSYNC lag, setting a limit of 0.007 below the refresh rate. So I tried 0.007 below my target VRR of 144, 143.993. The refresh rate overlay was just a constant 144 instead of flicking between 143 and 144, or 143/144/145 when set to 144 FPS.

In the end, I settled upon 150 Hz refresh rate, 143.993 FPS limit in RTSS, 150 FPS limit ingame (this didn't matter), VSYNC "Use 3D application settings". Results in a very smooth 144 Hz experience.

Anyway final points...
  • If your monitor overclocks, reduce the overclock until the the refresh rate stops spiking.
  • Use Rivatuner Statistics Server to limit the FPS.
  • Enable VSYNC in the control panel or "Use 3D application settings".
  • Don't use both ingame limiter and RTSS at the same value at the same time. Disable VSYNC and adjust the ingame limiter until microstuttering stops, this is when the ingame limiter doesn't negatively affect the RTSS limiter. Reenable VSYNC if you had it on.
  • Limit at least 3.5 FPS below refresh rate. Lower could be better, would need benchmarking.
Last edited by sekta on 07 May 2017, 01:52, edited 16 times in total.

User avatar
jorimt
Posts: 2481
Joined: 04 Nov 2016, 10:44
Location: USA

Re: G-Sync requiring very low FPS cap?

Post by jorimt » 04 May 2017, 10:22

RealNC wrote:This just in: Battle(non)sense found that the Creator's update is to blame, and that the fix is to use high performance mode in the power settings of windows:

https://www.youtube.com/watch?v=mVNRNOc ... u.be&t=287
Great video, as per usual.

I was actually in email correspondence with him during his initial testing; I was the one who suggested he test borderless vs fullscreen mode. He also asked me to try "High Performance" vs "Balanced," but I saw no difference. My going theory, is core parking, as I've had it disabled for years. It isn't disabled by default, but "High Performance" sets the CPU to its highest frequency, overrides all bios power settings, and (I believe) disables core parking.

One theory, and I could be wrong, but that's the only thing I can think of, because our systems were very similar otherwise.

I've been performing my input latency re-test over the past week and a half, and still going. I'm testing across all available refresh rates, so it's going to take a good while, but the results should be worth it.

I have crunched the numbers for a couple refresh rates so far however, and the built-in refresh rate meter fluctuation issue hasn't appeared to affect input latency at all.
(jorimt: /jor-uhm-tee/)
Author: Blur Busters "G-SYNC 101" Series

Displays: ASUS PG27AQN, LG 48CX VR: Beyond, Quest 3, Reverb G2, Index OS: Windows 11 Pro Case: Fractal Design Torrent PSU: Seasonic PRIME TX-1000 MB: ASUS Z790 Hero CPU: Intel i9-13900k w/Noctua NH-U12A GPU: GIGABYTE RTX 4090 GAMING OC RAM: 32GB G.SKILL Trident Z5 DDR5 6400MHz CL32 SSDs: 2TB WD_BLACK SN850 (OS), 4TB WD_BLACK SN850X (Games) Keyboards: Wooting 60HE, Logitech G915 TKL Mice: Razer Viper Mini SE, Razer Viper 8kHz Sound: Creative Sound Blaster Katana V2 (speakers/amp/DAC), AFUL Performer 8 (IEMs)

Glide
Posts: 280
Joined: 24 Mar 2015, 20:33

Re: G-Sync requiring very low FPS cap?

Post by Glide » 04 May 2017, 14:37

jorimt wrote:My going theory, is core parking, as I've had it disabled for years. It isn't disabled by default, but "High Performance" sets the CPU to its highest frequency, overrides all bios power settings, and (I believe) disables core parking.
That might be why I've not seen a difference between the Ryzen Balanced power plan and High Performance, as both disable core parking.

sekta
Posts: 16
Joined: 19 May 2015, 22:19

Re: G-Sync requiring very low FPS cap?

Post by sekta » 06 May 2017, 22:05

I found the issue for my rapid refresh rate fluctuation. It is the monitors overclock option, reducing it from 165 Hz to 150 Hz completely fixed the spiking. The ingame option (CSGO), even with High Performance power plan, also fluctuates wildly. VSYNC "Use 3D application settings" also performed more consistently.

I edited my post above, give it a read if you have a 165 Hz monitor, using GSYNC with RTSS, etc.

User avatar
RealNC
Site Admin
Posts: 3738
Joined: 24 Dec 2013, 18:32
Contact:

Re: G-Sync requiring very low FPS cap?

Post by RealNC » 07 May 2017, 08:27

I have none of these issues :-P I have a 165Hz monitor, but I don't use that function. I use 144Hz with fps_max 140.
SteamGitHubStack Overflow
The views and opinions expressed in my posts are my own and do not necessarily reflect the official policy or position of Blur Busters.

sekta
Posts: 16
Joined: 19 May 2015, 22:19

Re: G-Sync requiring very low FPS cap?

Post by sekta » 08 May 2017, 05:07

Lucky you. Try the overclock function and see if you can back me up with my findings.

I messed around with it some more in order to reduce the input lag. I wanted to use both the ingame limiter and RTSS at the same time. Didn't really matter what combination I did, with VSYNC disabled it had microstutter with pretty strong motion blur. Quite straining on the eyes. VSYNC fixes this so I enabled this and tried again. CS:GOs fps limiter seems to have at least a 10 Hz spread on my monitor and using it hit the Hz limit, even if RTSS alone was holding it below the Hz just fine. 146 RTSS was holding at 146 Hz perfect, with the ingame limiter enabled at 146 as well, it starts fluctuating and hits 150 Hz frequently. Combining the two needed a different limit.

So I set out to find the highest RTSS limit I could use with VSYNC and no ingame limiter without hitting 150 Hz AT ALL in the CS:GO FPS Benchmark map. At 144 or higher, it would spike to 150 Hz when exiting the smokes. At 143 it stopped. So the max limit is probably 142, but could be lower just to be safe. I repeated with the ingame limiter and no RTSS. The highest ingame limit was 146. Once again, maybe lower to be safe.

RTSS looks smoother but requires a lower limit. It holds up solid except for the infrequent spikes that occur, mainly while exiting the smokes during the benchmark. I think the creators update may be to blame for these spikes or its just gsync itself. Ingame fluctuates wildly but can have a higher limit.

Testing if a combination of ingame and RTSS was better than just the ingame, I tried out setting the ingame lower than RTSS to reap the input lag benefits, whilst using RTSS at the highest it can go without hitting the limit. I settled for 140 fps ingame limit and 142 fps RTSS. It performed well with vsync on, exiting smokes still had the upward spikes of RTSS alone, so the ingame limiter is spiking past 142 which triggers RTSS' limiter which spikes up to 149. With vsync off, it still had the eye straining motionblur microstutter. It didn't matter how low I set the ingame limiter, as long as the ingame limiter was limiting the FPS and RTSS was set to any value other than 0, it had the motionblur microstutter.

A combination of RTSS and ingame with vsync on is probably not the ideal solution because the frametime spikes were exacerbated when RTSS took over. I don't know if RTSS was beneficial at all on average or if the only thing it did was make the spikes worse. So I don't recommend this. Was a good idea at least, having RTSS 1 frame lag instead of VSYNC 2 frame lag when it spikes but doesn't really work.

A combination with vsync off is not usable at all. With the ingame limiter set above RTSS, it probably has zero effect at all. When I tried it with the ingame limiter close to RTSS, every time the fps spread dropped below the RTSS limit it had extreme microstutter motionblur. So I don't know if vsync on just masks this horrible combination or actually fixes it. RTSS does say to disable VSYNC if using the fps limiter.

So using a combination is bad when the ingame limiter takes over and the fps is below the RTSS limit. What about triggering the ingame limiter only when RTSS spikes above it's limit? Using the ingame limiter as the fallback limiter to prevent hitting the refresh rate. Maybe that can supplement the RTSS limiter. The closest I could get the ingame limiter to the RTSS limit was 147 without the ingame limiters fluctuation dropping below 143 and taking over. So I set it to 148 to be safe. I tried the CSGO benchmark map with 142 RTSS and 148 ingame, no microstutter or motionblur. Tried ingame. Didn't see/feel any difference to be honest. Did it help with RTSS' fluctuations? Don't know. Since I'm no longer hitting the limit with this set up, the last thing to do is re enable VSYNC to remove the bottom tearing and call it a day.

Vsync off vs on, honestly it was so hard to tell. With 142 RTSS and 148 ingame I restarted so many times with vsync off and vsync on. I feel like vsync off was consistently more snappier and vsync on felt variable, like smoothing but this could totally be placebo. I thought maybe the Hz was reaching the limit but it was solid 142. Maybe it needs a lower limit. Maybe vsync off is best when RTSS is the limiter?

Vsync off with RTSS 8 FPS below, ingame set at refresh rate as the fallback (maybe?) seems the best, coincidentally this hits the 142 fps recommended limit for 144 hz, so the 144 Hz rule may apply to all native 144 Hz IPS panels that have the 165 Hz overclock function, no matter what overclock it is set to. Meaning the overclock is well and truly a gimmick, not serving any purpose at all, not even extending the GSYNC range.
Last edited by sekta on 08 May 2017, 07:31, edited 4 times in total.

l33tgms
Posts: 3
Joined: 08 May 2017, 07:01

Re: G-Sync requiring very low FPS cap?

Post by l33tgms » 08 May 2017, 07:03

I dont get it so if I buy 60hz gsync panel I need to cap fps to 55 or something? Why the hell things wont work straight out of the box?

Sparky
Posts: 682
Joined: 15 Jan 2014, 02:29

Re: G-Sync requiring very low FPS cap?

Post by Sparky » 08 May 2017, 09:36

l33tgms wrote:I dont get it so if I buy 60hz gsync panel I need to cap fps to 55 or something? Why the hell things wont work straight out of the box?
Because nvidia doesn't make every game ever, and displays have a maximum refresh rate?

If you throw frames at a monitor faster than it can handle, you get one of three things:

Tearing(vsync off)
Lots of input lag caused by a queue of frames waiting to be displayed(vsync on)
Stuttering caused by dropped frames(fast sync)

A framerate limiter avoids that, and the best place to put that limiter(in terms of minimizing latency), is the game engine.

User avatar
jorimt
Posts: 2481
Joined: 04 Nov 2016, 10:44
Location: USA

Re: G-Sync requiring very low FPS cap?

Post by jorimt » 08 May 2017, 09:48

sekta wrote:Lucky you. Try the overclock function and see if you can back me up with my findings.
@sekta you're overthinking all of this, and solely testing by eye with a (likely currently buggy) built-in refresh rate meter is only going to get you so far.

I've been doing actual input latency tests with actual measurement equipment for two weeks now (WITH the Creators Update), and I can assure you, that at 144/165Hz with G-SYNC + v-sync on (Nvidia Control Panel) + fullscreen mode + in-game FPS limit of 3 below your current refresh, single, complete, tear-free frames are being displayed to your monitor as fast as the scanout rate (and your system) will allow.

Also, avoid "Adaptive G-SYNC" (G-SYNC + v-sync off), as it will tear at any point it think it can't adhere to the current scanout period, which will happen at any point there is a sudden frametime difference between one frame and the next.

Any other behaviors you are experiencing are down to your system and/or specific configuration issues.
(jorimt: /jor-uhm-tee/)
Author: Blur Busters "G-SYNC 101" Series

Displays: ASUS PG27AQN, LG 48CX VR: Beyond, Quest 3, Reverb G2, Index OS: Windows 11 Pro Case: Fractal Design Torrent PSU: Seasonic PRIME TX-1000 MB: ASUS Z790 Hero CPU: Intel i9-13900k w/Noctua NH-U12A GPU: GIGABYTE RTX 4090 GAMING OC RAM: 32GB G.SKILL Trident Z5 DDR5 6400MHz CL32 SSDs: 2TB WD_BLACK SN850 (OS), 4TB WD_BLACK SN850X (Games) Keyboards: Wooting 60HE, Logitech G915 TKL Mice: Razer Viper Mini SE, Razer Viper 8kHz Sound: Creative Sound Blaster Katana V2 (speakers/amp/DAC), AFUL Performer 8 (IEMs)

l33tgms
Posts: 3
Joined: 08 May 2017, 07:01

Re: G-Sync requiring very low FPS cap?

Post by l33tgms » 08 May 2017, 09:54

Sparky wrote:
l33tgms wrote:I dont get it so if I buy 60hz gsync panel I need to cap fps to 55 or something? Why the hell things wont work straight out of the box?
Because nvidia doesn't make every game ever, and displays have a maximum refresh rate?

If you throw frames at a monitor faster than it can handle, you get one of three things:

Tearing(vsync off)
Lots of input lag caused by a queue of frames waiting to be displayed(vsync on)
Stuttering caused by dropped frames(fast sync)

A framerate limiter avoids that, and the best place to put that limiter(in terms of minimizing latency), is the game engine.
What a bunch of nonsense why even bother to answer to a rhetorical question especially that kind of stupid things
The point was to get a flawless working tech that limit everything out of the box (especially if you pay for it extra or at least without 3rd party software) but you for an unknown reason say that they don't make every game and so on ROFL god you made my day how is that even related :lol: at least you partially understand some of the 1st grade basics haha

Post Reply