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.



509 Comments For “G-SYNC 101”

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Radlyng
Member
Radlyng

So from my understanding I want to cap my fps to 238-237 and keep g-sync and v-sync (from nvidia 3d settings) on

sleepynoodle
Member
sleepynoodle

Why do you think that basically no (to my understanding) cs:go pros use these settings or anything similar? Just regular settings with no capped FPS. Is it lack of knowledge or what do you think?

doodles
Member
doodles

Hey jorimt,

Just a quick question after reading your guide on G-sync + V-sync and input lag…

So I understand that if G-sync is used in combination with V-sync, it would essentially be forcing the computer to deliver steady frame timing over the period over a second (so for 144 Hz they would all be 6.9 ms versus the 144 frames averaging out to 6.9 ms). Also from what I understand, all of this discussion is related to changing these settings withing the NVIDIA control panel.

What does this mean with regards to in-game settings say for a game like Apex Legends or Modern Warfare? Do we have ENABLE V-sync within the individual games as well, to see the benefits from the G-sync + V-sync settings in the Control Panel? Or is doing so not necessary, and might cause other issues?

Vegetariano
Member
Vegetariano

Hello, jorimt.

This guide just rocks. I have just one question about the new Nvidia driver setting “Max Frame Rate”. From now on, I can set the maximum frame rate that the GPU will render a game directily in the driver.

Is there a difference in latency between set the max FPS at the driver new option or in the RTSS?

Thank you!

andregm3
Member
andregm3

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