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.



2042 Comments For “G-SYNC 101”

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zikalol
Member
zikalol

Hi, i have a dell freesync monitor. The issue is when i enable Gsync the monitor turns off mid-game. can’t figure out what is causing this issue. thank you

Zanity
Member
Zanity

Hi, quick question, why do we still need to set 3 fps lower if we use nvidia ultra low latency mode ? which automatically force caps the frame rate lower already. thanks

Zehdah
Member
Zehdah

Hi Jorimt. I’m just wondering if the “variable refresh rate” option in Windows 10 graphics settings should be enabled or disabled or if it makes no difference? I use a Gsync monitor.

domfak
Member
domfak

Hello,

Want to thank you for all the info in this page.
Also I have couple of questions:

I got RTX 3080 + 165hz monitor, I am having those tearing lines on my low side of display if I play with GSync + uncapped fps. Sometimes it feels like stuttering. So I decided to try your method.
But where are some issues in game COD: Warzone:

1) GSync On + Vsync ON + LLM (Ultra) + Reflex On + Boost – caps my FPS in game at 60. Why?

2) GSync On + Vsync FAST + LLM Ultra + Reflex On+ Boost – I can cap myself at 161fps as you proposed. And FPS are dipping from 140 to 161. Also with thise method I found that blur line in the bottom of the screen still exist.

What is difference between VSync ON / VSync Fast?
Will I get more input delay in this case?
Also can I feel that option with Gsync + Vsync has more input delay on my mouse or it is only placebo?

Thanks for an answer.

majkool
Member
majkool

1. So with 390Hz monitor input lag with GSYNC + VSYNC and 386fps game limitter is nearly the same like with GSYNC/VSYNC off and fps_max 0 in CSGO.
2. I know that with 240Hz monitor there is a few ms delay with these options but I think it’s still better to accustom to it and play on a pro level?

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