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.



1611 Comments For “G-SYNC 101”

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Zole
Member
Zole

After reinstalling windows recently, my G-Sync behaviour has changed.

As far as I can remember, my usual set up was:
League of legends played in Windowed Borderless Mode.
v-sync: disabled – in-game
v-sync: enabled (set to “Fast”) – in NVCP
g-sync: enabled for both windowed and full-screen – in NVCP
preferred refresh rate: Highest available – in NVCP
power management: Prefer maximum performance – in NVCP
Monitor technology: G-SYNC – in NVCP
frame rate: uncapped – in game

With these settings, my frame rate was capped by the fast v-sync to 1 frame below my monitors max refresh rate 164 (down from 165).

However, after reinstalling windows and reapplying these same settings the frame rate is no longer capped to 1 below the monitors refresh rate. Instead I get FPS anywhere from 200-600 and I notice stutters and tearing.

Is there any way for me to get back my previous system behaviour?

PS I know the recommended way to set up a system is for full-screen g-sync but I prefer windowed borderless for the rapid alt tabbing, as I do that frequently.

brdon209
Member
brdon209

I am looking to buy a 1440p 144hz monitor and from what I have read, I should set my FPS at 141 using nvcp, set vsync on in nvcp and off in game. However, many sources have told me to turn on null on and others have told me to completely turn it off. Should I put it on ultra, on or off? I play league of legends fyi and my cpu is usually around 16% usage and my gpu is around 30% uncapped 1080p. Sorry, I am new to th this subject .

georgi74
Member
georgi74

I have a System with a Geforce 3080 and as display I use a LG c9 OLED TV with 120Hz and GSync.

In Nioh 2, which can easily perform over 120 fps with DLSS on 4k with that System if I limit the game to 117 fps with RTSS I get Micro Stutter when just looking around. If I disable the RTSS limiter and let the game limit the fps to 120 (in game there is only an option to lock at 30/60/120) the game is buttery smooth. Is there any way to get the game running smooth with a limit to 117 fps?

loldayus
Member
loldayus

So recently Rocket League decided to change its in-game FPS limiter from a slider (where I could set my FPS to 141 exactly) to a drop-down menu with pre-configured FPS values in it, i.e. 30, 60, 90, 120, 144, etc. I have a 144 Hz monitor and I have V-Sync and G-Sync enabled in NVCP but used the in-game FPS limiter when it was more precise.

Would I be better off switching to the new and improved NVCP limiter so I can specify 141 FPS exactly or am I “safe” to use the in-game’s drop down’s “144” without the concerns that come with setting the FPS to EXACTLY the monitor’s refresh rate? Looking to optimize performance so lower input lag and minimization of in-between frames “hiccups” are desired.

Zehdah
Member
Zehdah

Made a comment earlier but it doesn’t show up, not sure if it’s just delayed or was removed, if it shows up with this then sorry for double comment, but I wanted to ask another question if I may: If my GPU usage is 95- 99%, and I’m around 100 fps so no where near my refresh rate of 144, should I use low latency mode?

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