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.



576 Comments For “G-SYNC 101”

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Zehdah
Member
Zehdah

If I get a 240 Hz monitor, like the BenQ ZOWIE XL2546, should I still be using the method above (Gsync on, Vsync off in game, on in control panel and cap FPS to 237 with RTSS) or should I uncap my framerate with Vsync and Gsync off? The reason I ask is a lot of pros in FPS games such as Apex, Siege, CSGO, seem to do the latter and I can’t understand why, unless G-sync isn’t available on those monitors, but I read that G-sync is available on freesync monitor’s now with 10xx and above cards, am I wrong? Greatly appreciate any input!

DanWensing
Member
DanWensing

Which one has the lowest input lag?
1. Gsync + Vsync + Low Latency Mode at Ultra (no fps limit)
2. Gsync + Vsync + NVC/RTSS fps limit (3fps below Refresh rate)

DanWensing
Member
DanWensing

Hi, I understand that we should use Vsync On when using Gsync. But with the new LG OLED C9, which is gsync compatible, if I have Vsync “ON” I get some microstutter every 10s or so. But if I keep vsync off, the game is 100% smooth (I have the FPS capped at 3fps below the TVs refresh rate). One friend of mine has the same issue with his C9. Do you know why this is happening?

BlackStorm82
Member
BlackStorm82

(Gsync off/Gsync not supported) 144hz 144fps CAP(ingame) (no v-sync) this

144hz 139fps cap(ingame) (no v-sync)
Is it correct to lose input lag than condition?

If I turn off v-sync, is it the same as 139 or 144 cap?
Is a 139fps limit good for 144hz even on a regular monitor? in a v-sync off.
Sorry for the beginner. i love blurbusters

ezidifn
Member
ezidifn

i have a 144hz AMD freesync monitor. How should i get the leasy amount pf input lah? By enabling G sync on nvidia and cap hz at 142/141?

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