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G-SYNC 101: G-SYNC vs. V-SYNC w/FPS Limit

Published Jun 20, 2017 by in: G-SYNC

So Close, Yet So Far Apart

On the subject of single, tear-free frame delivery, how does standalone double buffer V-SYNC compare to G-SYNC with the same framerate limit?

Blur Buster's G-SYNC 101: Input Latency & Optimal Settings
Blur Buster's G-SYNC 101: Input Latency & Optimal Settings
Blur Buster's G-SYNC 101: Input Latency & Optimal Settings
Blur Buster's G-SYNC 101: Input Latency & Optimal Settings
Blur Buster's G-SYNC 101: Input Latency & Optimal Settings
Blur Buster's G-SYNC 101: Input Latency & Optimal Settings

As the results show, but for 60Hz (remember, a “frame” of delay is relative to the refresh rate), the numbers are relatively close. So what’s so great about G-SYNC’s ability to adjust the refresh rate to the framerate, if the majority of added input latency with V-SYNC can be eliminated with a simple FPS limit? Well, as the title of this section hints, it’s not quite that cut and dry…

While it’s common knowledge that limiting the FPS below the refresh rate with V-SYNC prevents the over-queuing of frames, and thus majority of added input latency, it isn’t without its downsides.

Unlike G-SYNC, V-SYNC must attempt to time frame delivery to the fixed refresh rate of the display. If it misses a single one of these delivery windows below the maximum refresh rate, the current frame must repeat once until the next frame can be displayed, locking the framerate to half the refresh rate, causing stutter. If the framerate exceeds the maximum refresh rate, the display can’t keep up with frame output, as rendered frames over-queue in both buffers, and appearance of frames is delayed yet again, which is why an FPS limit is needed to prevent this in the first place.

When an FPS limit is set with V-SYNC, the times it can deliver frames per second is shrunk. If, for instance, the FPS limiter is set to 59 fps on a 60Hz display, instead of 60 frames being delivered per second, only 59 will be delivered, which means roughly every second a frame will repeat.

As the numbers show, while G-SYNC and V-SYNC averages are close over a period of frames, evident by the maximums, it eventually adds up, causing 1/2 to 1 frame of accumulative delay, as well as recurring stutter due to repeated frames. This is why it is recommended to set a V-SYNC FPS limit mere decimals below the refresh rate via external programs such as RTSS.

That said, an FPS limit is superior to no FPS limit with double buffer V-SYNC, so long as the framerate can be sustained above the refresh rate at all times. However, G-SYNC’s ability to adjust the refresh rate to the framerate eliminates this issue entirely, and, yet again, beats V-SYNC hands down.

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3878 Comments For “G-SYNC 101”

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Apache3m
Member
Apache3m

Naturally, with MFG enabled, Reflex limits my FPS from 240 to 224; however, if I disable V-Sync in the Nvidia Control Panel, I hit 240 FPS with MFG on.

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3 days 10 hours ago
Apache3m
Member
Apache3m

Hi – I have a setup with a 9800X3D and an RTX 5080, along with an MSI 321URX QD-OLED monitor.
Could you tell me what I should do when gaming with NVIDIA’s Frame Gen (MFG) enabled? Should I stick with the G-Sync + V-Sync + Reflex settings, or do you recommend something else?

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3 days 10 hours ago
jorimt
Author
jorimt

My VRR recommendations remain unchanged with or without FG; whether FG conflicts with VRR is on FG implementation itself, in which case, no amount of fiddling with VRR settings will typically change that anyway.

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3 days 7 hours ago
pangtali
Member
pangtali

For Low Latency Mode what if an FPS limiter is already in use, reflex is not available, but fps always exceed refresh rate?

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5 days 54 minutes ago
jorimt
Author
jorimt

Are you referring to LLM “On” or “Ultra?”

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4 days 22 hours ago
pangtali
Member
pangtali

Yes

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4 days 22 hours ago
jorimt
Author
jorimt

The answer will depend on if you’re using LLM “On” or “Ultra,” as such, again, which are you referring to in your posed scenario?

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4 days 22 hours ago
pangtali
Member
pangtali

I always have G-Sync and V-Sync on in all the games I play, and my FPS is usually above my refresh rate. I like to cap it at 224 when Reflex isn’t available so my FPS and frametimes are more stable. So, I’m wondering if LLM “On” or “Ultra” is better for games that don’t have Reflex.

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4 days 22 hours ago
jorimt
Author
jorimt

As already noted in https://blurbusters.com/gsync/gsync101-input-lag-tests-and-settings/14/, in supported DX12 and older games with G-SYNC + V-SYNC on, “Ultra” will set an automatic ~224 FPS limit at 240Hz, whereas “On” won’t.

Further, both forms of LLM will only reduce latency whenever your GPU usage is 99%+, and they won’t whenever GPU usage is below 99%. Same goes for Reflex.

LLM is technically also inferior to both Reflex (where available) or even a manual FPS limit that prevents maxed GPU usage in that scenario.

Thus, for the render-queue-level latency these type of settings specifically reduce, it’s Reflex > Manual FPS limit that prevent 99% GPU usage > LLM “Ultra” > LLM “On” in order of effectiveness.

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4 days 21 hours ago
pangtali
Member
pangtali

Thank you for explaining. I have another question unrelated to LLM. Would I get lower latency in Valorant by playing uncapped with G-Sync and V-Sync off while keeping Reflex On + Boost enabled, or by using G-Sync, V-Sync, and Reflex On + Boost?

G-Sync On
V-Sync On
Reflex On + Boost enabled
FPS (capped by Reflex) = 225

Vs

G-Sync Off
V-Sync Off
Reflex On + Boost enabled
Avg FPS uncapped = 350

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4 days 21 hours ago
jorimt
Author
jorimt

G-SYNC off + V-SYNC off + uncapped/capped above your physical refresh rate will always be the lowest possible latency (with or without Reflex), because it tears.

Tearing is your direct latency reduction over G-SYNC on + V-SYNC on + Reflex.

As for the “Boost” portion of Reflex, it just ensures your GPU clock doesn’t drop below its base boost speed.

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4 days 20 hours ago
tenki
Member
tenki

Hello,

Thank you for your amazing guide, I am always following it very carefully and it was for me an immense help.

I have some questions though because I think that my setup is not 100% optimized

I have a desktop MSI QD-Oled 360hz 1440p, but I switch the refresh rate to 120hz because I usually do not play games more than 120fps , and my desktop gaming have a 5080 GPU and 9859X3D Ryzen.

For my questions:

– In NVCP I have like your guide and I have have v-synch set to default, gsync on only for full screen and LLM off. In game I have for sure V-sync on. I have no idea if it is better to cap the frame rate to 116fps with NVCP or RTSS because sometimes in game I have frequently shutterings when I cap, no matter what game is. Should also be cause because LLM Is off?

– Based on the question before, I don’t understand when it is the case to enable the limiter in game. Should it be a slider or more like a selectable option ( 60fps, 120fps, uncapped etc). I usually have every time uncapped, but is there a certain rule for it?

– sometimes in games I go over 120fps and oscillates every time , but not reaching 120fps or less. Though when I cap, I even go down ( not stable) , how is that possible? Should I not cap

– OLED on 240hz is flickering so much with G-sync, this is another reason why I put 120hz, but if you suggest to put 240hz and that’s it let me know.

Thank you so much in advance and sorry for my long comment!

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21 days 3 hours ago
jorimt
Author
jorimt

I have a desktop MSI QD-Oled 360hz 1440p, but I switch the refresh rate to 120hz because I usually do not play games more than 120fps

Not recommended, unless you have a very specific reason.

Otherwise, keep it at the highest supported physical refresh rate of your display. Else, it’s just slowing frame delivery with VRR, regardless of achievable framerate.

I.E. 120 FPS 360Hz VRR is lower latency than 116FPS 120Hz VRR.

I have no idea if it is better to cap the frame rate to 116fps with NVCP or RTSS because sometimes in game I have frequently shutterings when I cap, no matter what game is. Should also be cause because LLM Is off?

Based on the question before, I don’t understand when it is the case to enable the limiter in game. Should it be a slider or more like a selectable option ( 60fps, 120fps, uncapped etc). I usually have every time uncapped, but is there a certain rule for it?

Which framerate limiting method you use for what game/when is honestly down to situation and preference; they’re all very close where latency is concerned nowadays.

For reference, a “good” in-game limiter will only reduce overall latency by around 1/2 frame over RTSS, and it won’t usually achieve as stable of frametime performance.

Finally, FPS limiters nor VRR prevent all forms of stutter, so you’ll still experience unavoidable system-side stutter here and there, more or less depending on the game/engine.

sometimes in games I go over 120fps and oscillates every time , but not reaching 120fps or less. Though when I cap, I even go down ( not stable) , how is that possible? Should I not cap

If you mean your set limit doesn’t always keep frametime smooth, that’s because whenever your framerate naturally falls below the limit, or spikes above it, the limiter has no control over regulation in those instance; only when the average framerate is actually limited by the limiter is it in effect.

OLED on 240hz is flickering so much with G-sync, this is another reason why I put 120hz, but if you suggest to put 240hz and that’s it let me know.

OLED VRR flicker is entirely dependent on frametime performance; the more sporadic it is, the worse the flicker is, regardless of the physical refresh rate you have set.

As such, I’d suggest you use RTSS (since it tends to have the steadier frametime performance of most limiters available), and set the limit to an average your system can sustain 99% of the time in the given game.

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21 days 3 hours ago
tenki
Member
tenki

Thank you so much for the response

Not recommended, unless you have a very specific reason.

Otherwise, keep it at the highest supported physical refresh rate of your display. Else, it’s just slowing frame delivery with VRR, regardless of achievable framerate.

I.E. 120 FPS 360Hz VRR is lower latency than 116FPS 120Hz VRR.

So for this it is because of 10p colours on my Nvidia ( the range of colour in the setting as 240hz and 360 does not support it unless I set with my monitor with DSC enabled) . No idea if it is better to activate DSC and put 10p, disable it and put 8p at 360hz ( like you suggest) or any other combination scenario. Also Should I set it at 120 FPS at this point and keep enable gsync at this point ( I think I should keep enable and set It up like you said)

Which framerate limiting method you use for what game/when is honestly down to situation and preference; they’re all very close where latency is concerned nowadays.

For reference, a “good” in-game limiter will only reduce overall latency by around 1/2 frame over RTSS, and it won’t usually achieve as stable of frametime performance.

Finally, FPS limiters nor VRR prevent all forms of stutter, so you’ll still experience unavoidable system-side stutter here and there, more or less depending on the game/engine.

So you still suggest at this point to try the in game one to see how it runs and use RTSS as general limiter ( safe bet)? The only thing is if I can’t cap to 116 is it still viable?

If you mean your set limit doesn’t always keep frametime smooth, that’s because whenever your framerate naturally falls below the limit, or spikes above it, the limiter has no control over regulation in those instance; only when the average framerate is actually limited by the limiter is it in effect.

It is still strange that it can sustain an average frame limit, but produce more where I don’t set it T.T

OLED VRR flicker is entirely dependent on frametime performance; the more sporadic it is, the worse the flicker is, regardless of the physical refresh rate you have set.

As such, I’d suggest you use RTSS (since it tends to have the steadier frametime performance of most limiters available), and set the limit to an average your system can sustain 99% of the time in the given game.

Will I achieve this with trial and error and RTSS async or reflex limiter?

Thank you so much in advance for all the nice tips . I struggle so much with lagging and shuttering too much on any game , this is why and I upgraded my desktop to avoid it T.T

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21 days 16 minutes ago
jorimt
Author
jorimt

So for this it is because of 10p colours on my Nvidia ( the range of colour in the setting as 240hz and 360 does not support it unless I set with my monitor with DSC enabled) . No idea if it is better to activate DSC and put 10p, disable it and put 8p at 360hz ( like you suggest) or any other combination scenario.

It can depend on the effectiveness of the HDR implementation on your monitor, but there is typically very little visual difference between 10-bit HDR and 8-bit HDR in PC games.

That said, if you’re looking to keep DSC disabled, then you should definitely at least keep your physical refresh rate at 240Hz instead of 120Hz when using VRR.

So you still suggest at this point to try the in game one to see how it runs and use RTSS as general limiter ( safe bet)? The only thing is if I can’t cap to 116 is it still viable?

If you’re picky about general latency, performance, and stutter, then you’re going to have to experiment with and tune each of your games. There’s no one-size-fits-all, set-and-forget method, unless of course you lower your standards and just accept inconsistent performance from game to game.

Every system has a performance “budget,” and if you exceed that budget, you start getting more performance issues. A.K.A. worse frametime performance, which will = more stutter.

In other words, perhaps both system “A” and “B” can run X game at a 120 FPS average, but system “B” is too weak vs. “A” overall to run it at that same average framerate as consistently.

Thus, even if your system can push a higher average framerate, it may not be worth the frametime inconsistency it causes to achieve it.

It is still strange that it can sustain an average frame limit, but produce more where I don’t set it T.T

Not sure if I’m misunderstanding you here, but the very reason for an FPS limit is to “limit” it below a number that would otherwise be higher without the limiter.

Will I achieve this with trial and error and RTSS async or reflex limiter?

If you’re trying to achieve the most stable frametime as to avoid as much OLED VRR flicker as possible, then you want to use RTSS Async, not the RTSS-level Reflex limiting method in this case.

As for how you should determine what to set the limit at in the given game, you can typically try to find the most demanding scene in the game while your framerate is uncapped, and then set your limit slightly below that.

For instance, if your game runs uncapped between 80 and 120 FPS, you’d set the limit at around ~75 for the highest possible consistency/stability, or if it’s between 125 and 270 FPS uncapped, you’d limit it around ~120, and so on…

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20 days 22 hours ago
asari7k
Member
asari7k

im still a bit confused. so i want to play dbfz at the lowest latency possible bc its a fighting game capped at 60 fps and im playing on a 240hz monitor. so whats better g sync + v sync (in ncvp) on with low latency mode on ultra or just disable g sync and v sync but low latency stil on ultra . bc ive seen some videos on youtube that tested capped 60fps games at higher refres rate and it gives lower latency so when i use g sync is automaticly caps it at 60hz so doesnt that just completly ruin the g sync vs v sync setup ?

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30 days 21 hours ago
jorimt
Author
jorimt
  1. G-SYNC off + V-SYNC off + 60 FPS + 240Hz physical refresh rate = will tear, lowest possible latency
  2. G-SYNC on + V-SYNC off + 60 FPS + 240Hz physical refresh rate = can tear, second lowest latency, as it sometimes won’t tear
  3. G-SYNC on + V-SYNC on + 60 FPS + 240Hz physical refresh rate = can’t tear, lowest possible tear-free latency
  4. G-SYNC on/off + V-SYNC on/off + 60 FPS + 60Hz physical refresh rate = highest latency, and should not be used in place of #1-3 on a higher refresh rate monitor

Basically, 60 FPS 60HZ VRR should be avoided over 60 FPS 240Hz VRR in your posed scenario.

The latter scenario means that, yes, while G-SYNC will refresh the display 60 times per second, each frame will scan in at a much faster ~4.2ms per at a 240Hz physical refresh rate vs. 60 FPS at 60Hz, where it will still refresh the display 60 times per second, but scan in each frame at a much slower 16.6ms per.

As for LLM Ultra, it reduces render queue latency separate of the sync latency that properly configured VRR reduces, but settings like LLM can only further reduce latency in all of the above scenarios if your GPU usage is 99% or above; if below 99%, it won’t reduce latency any further.

Thus, for DBFZ internally capped at 60 FPS, lowest possible latency on a 240Hz monitor is going to be G-SYNC off + V-SYNC off, lowest possible tear-free latency is going to be G-SYNC on + V-SYNC on, and LLM/Ultra will do nothing to reduce latency on top of that unless GPU usage is at 99%+…and that’s about it.

The rest is down to the inherent latency of your input device(s) and the performance of your ISP/internet connection (when playing online).

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30 days 20 hours ago
acecond
Member
acecond

Hey, I recently went back to gaming at a capped 60 FPS again using RTSS, and I have a 165 Hz monitor. With VRR enabled, what refresh rate should I set my monitor to for the smoothest and best 60 FPS experience? (Currently using 120 Hz with VRR)

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27 days 3 hours ago
jorimt
Author
jorimt

what refresh rate should I set my monitor to for the smoothest and best 60 FPS experience?

It should be set to the highest physical refresh rate your display supports for the lowest possible latency/fastest possible frame delivery.

With VRR, current physical refresh rate equals per-frame scan in speed; the higher the refresh rate, the faster the scanout, regardless of achievable average framerate.

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27 days 3 hours ago
acecond
Member
acecond

Makes sense. What if I’m playing older games or emulators that don’t play well with VRR, though? Should I still keep it capped at 165 Hz? (This is mostly why I play with 120 Hz on 60 fps.)

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24 days 2 hours ago
Mark Rejhon
Admin
Mark Rejhon

Emulators are self-capping at 60fps or 50fps, so no external cap necessary unless the internal emulator cap is very jittery.

Rare: Some people try to tame a very stuttery emulator with an external microsecond-precise cap (RTSS) set to about 0.01 to 0.1fps above your emulator’s self-cap.

Advanced complex dual cap approaches (main internal lag-saving cap / external stutter-reducer cap) are rare but are sometimes used for content that still stutter despites its internal cap. This is where the internal cap saves lag (but is very stuttery, like varying 58fps-62fps) and the other is a backup external cap that prevents stutter (makes the framepacing glassfloor). Always set the outer/backup frame rate cap higher than the inner/main frame rate cap. And always remember that 60fps-locked content is considered an internal cap already. Do not try the dual cap method unless you 100% understand everything else already (like 2nd year university after 1st year university pre-requisites). Dual caps will always make things worse unless you know what you’re doing. But it works in niche cases.

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23 days 54 minutes ago
jorimt
Author
jorimt

There are few older games or emulators that don’t work with VRR, but for those very rare circumstances, it depends on if you’re then relying on standalone V-SYNC or no-sync for what I assume are games predominately hard-locked to 60 FPS or lower.

In that scenario, the highest possible refresh rate with no-sync is still optimal, but with standalone V-SYNC, yes, a physical refresh rate evenly divisible by 60/30 is technically preferable to a physical refresh rate that isn’t evenly divisible, even if the latter is higher than the one that is (165Hz vs. 120Hz in your case).

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23 days 6 hours ago
acecond
Member
acecond

Alright, thanks!

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23 days 2 hours ago
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