G-SYNC 101: G-SYNC Fullscreen vs. Borderless/Windowed


DWM Woes?

Requested by swarna in the Blur Busters Forums, is a scenario that investigates the effects of the DWM (Desktop Windows Manager, “Aero” in Windows 7) on G-SYNC in borderless and windowed mode.

Unlike exclusive fullscreen, which bypasses the DWM composition entirely, borderless and windowed mode rely on the DWM, which, due to its framebuffer, adds 1 frame of delay. The DWM can’t be disabled in Windows 10, and uses it’s own form of triple buffer V-SYNC (very similar to Fast Sync) that overrides all standard syncing solutions when borderless or windowed mode are in use.

To make sure this was the case, all combinations of NVCP and in-game V-SYNC, as well as the Windows 10 “Game Mode” and “fullscreen optimization” settings were tested to see if DWM could be disabled, and tearing could be introduced; it could not be, so Game Mode and fullscreen optimizations were disabled once again, and NVCP V-SYNC was re-enabled across scenarios for consistency’s sake.

The question is, does DWM add 1 frame of delay with G-SYNC using borderless and windowed mode?

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

Overwatch, shows that, no, with G-SYNC enabled, both borderless and windowed mode do not add 1 frame of delay over exclusive fullscreen. Standalone “V-SYNC,” however, does show the expected 1 frame of delay.

CS:GO was also tested for corroboration, and ought to have the same results, as DWM behavior is at the OS-level and should remain unchanged, regardless of the game…

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

Sure enough, again, G-SYNC sees no added delay, and V-SYNC sees the expected 1 frame of delay.

Further testing may be required, but it appears on the latest public build of Windows 10 with out-of-the-box settings (with or without “Game Mode”), G-SYNC somehow bypasses the 1 frame of delay added by the DWM. That said, I still don’t suggest borderless or windowed mode over exclusive fullscreen due to the 3-5% decrease in performance, but if these findings are true across configurations, it great news for games that only offer a borderless windowed option, or for multitaskers with secondary monitors.



1873 Comments For “G-SYNC 101”

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blaskovic
Member
blaskovic

Hi jorimt. I have a question for you. Sometime in older games (2011 – 2013) I have a drop frame from 144 to 140 or 144 to 135 and I notice this microstutter with G-sync but in other games if I have this drops (for example in Dirty Rally) I don’t see anything. My question is this: Why in some case (games) G-Sync seems works but in other circumstances (games) i see this microstutter? G-Sync shouldn’t avoid Microstutter? Thank you

stadiofriuli
Member
stadiofriuli

I’ve got a question. Got the Dell S2721DGF(A) which is G-Sync compatible, I’m running the monitor at 165Hz.

So what I basically did is to set a FPS cap @161 with RTSS.

Enabled G-Sync fullscreen in NVCP.

Enabled V-Sync in NVCP.

According to the guide V-Sync within the G-Sync range should still act like for native G-Sync monitors when it’s an official supported G-Sync compatible monitor.

What happens for me though is.

When V-Sync is enabled FPS cap at 158, not 161 as set in RTSS.

When I then disable V-Sync and have only G-Sync running it’s capped at 161 again.

So my question really is why this weird behaviour?

Should I activate or deactivate V-Sync in my case?

SvenL
Member
SvenL

Hi,
First of all, thank you so much for creating such an amazing guide. After reading through a few more questions arose.

I’m playing Warzone (FPS game) on a 1080p 144hz free sync monitor with an RTX 2080Ti graphics card. (I achieve 170-180 fps in game uncapped, which is above the refresh rate of my monitor)

My goal is to have a 100% tear-free gaming experience with the least amount of input lag to achieve the best possible accuracy.

First, I took over the following settings from you
NVCP: G-Sync & V-Sync: On

But when it comes to the FPS limiter, I’m still unsure which is best in my case. (Warzone also supports reflex)

In-Game FPS Limiter (141 FPS cap)
Reflex: On / On + Boost
RTSS / NVIDIA’s Max Frame Rate (141 FPS cap)

The question is which of these options has the lowest input lag and at the same time the most constant possible frame time. (I assume these 2 factors are especially important for FPS games)
Or what you think would be the best sweet spot out of all of these options.

With reflex activated (On + Boost), I noticed that the frame rate varies (around 138 fps). I’m not sure whether this will have a negative impact on my frame time or input delay, as I could easily achieve a constant 141 FPS with my graphics card. Should I then prefer the in-game FPS limiter or RTSS / NVIDIA’s Max Frame Rate over reflex?

Thank you very much

RoseGoldCrobat
Member
RoseGoldCrobat

I signed up here since you seem to know a lot about this. I have a very strange issue.

I have a monitor that is Gsync compatible and Gsync is on in fullscreen mode.

When I play certain games, the current ones I’ve seen it in are Red Dead Redemption 2 and Hitman 3 I would like to have gsync on and vsync on. The problem is when both settings are on at the same time my FPS caps to 72 fps, half of my monitor’s refresh rate. I don’t understand why this is happening. Could I be missing a setting?

Zehdah
Member
Zehdah

Hello. I have a new monitor, it’s a Samsung G7 Odyssey which is 1440p 240hz with Gsync. I’m wondering what you would recommend for optimal performance/gaming with that setup since it’s unlikely I will hit 240hz in a game at 1440p with a 1080ti, should I still follow the above instructions and cap to 237 along with vsync on in CP, off in game? Curious if there’s any extra things I need to do.

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