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.



662 Comments For “G-SYNC 101”

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BlackStorm82
Member
BlackStorm82

HI
“fixed refresh rate”
Do you have information about?

Is it correct that G-Sync does not work when I use this?
In-game [frame limit release mode]
When it comes to monitor technology G-Sync, 100-600 FPS was also released.

[fixed refresh rate]
When I activated the League of Legends with this function, 300FPS was fixed.

rocet
Member
rocet

Hi, maybe i’m misreading or misunderstanding the graphs/article but there is no downside to just using G-Sync ON + V-Sync OFF + No fps limit?

G-sync would activate when below 144fps and then ‘de-activate’ above 144? Causing no input lag?

Zehdah
Member
Zehdah

I know that for the lowest possible input lag, you want to find the highest framerate your system can achieve an average of 95-99% of the time without maxing your GPU usage and cap your framerate there with an in game limiter, but what do I do to achieve that in a game like Warzone where my FPS can be as low as 140 in big open areas or as high as 240 when inside a building or small area?

My CPU and GPU usage always seem to be very high at 85-97%. I have an i7 9700k and 1080ti, playing on a 240hz monitor. The game seems to be poorly optimized so I’m struggling to decide what to do.

fanatycme
Member
fanatycme

When I play DOTA 2, my fps is all the time at ~117 because i capped it, but at the end of the game, when match finishes the base gets destroyed and i get a FPS DROP from ~117 fps to 80-90 fps and my game STUTTERS, is it normal? i am playing with g sync, vsync and fps cap, i thought gsync is supposed to GET RID of stutter or I do SOMETHING WRONG?? during the rest of the game everything seems ok

i am using:
-nvcp: gsync on fullscreen, highest refresh rate, vsync let 3d app decide
-dota2: vsync on, fps max 117 (120hz monitor), highest video settings
-latest drivers, gtx 1070, monitor aw3418dw

AnonymousH
Member
AnonymousH

I typically prioritize input latency and thus normally run with G-SYNC but without any framerate limit or V-Sync, which causes some tearing at high framerates. I initially thought that Fast Sync eliminates tearing but introduces some microstutter, and that was all, making it a viable option in combination with G-SYNC, and the rest depends on preference (with G-SYNC: none = tearing, V-Sync + framerate limit = higher latency, Fast Sync = microstutter). However, if I’m reading this correctly, even G-SYNC + Fast Sync without a frame limit isn’t recommended because it limits the framerate to something lower than the monitor refresh rate, or runs starting at that slightly lower framerate?

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