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.



2611 Comments For “G-SYNC 101”

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Alex UA6
Member
Alex UA6

Hey brother, sorry to bother you again but I’m confused about one thing so in the game I play insurgency sandstorm it does not support freesync or Gsync. So in game I have limited my frames to my monitors, refresh rate, and enabled Vsync so I don’t get screen tearing. If I disable Vsync it’s unbearable. If in a newer game like modern warfare 2 would I want Vsync disabled? Also, if there’s anything you can tell me about the set up for insurgency, please feel free to let me know.

tbowly
Member
tbowly

is this normal? i have 60 stable fps on my 165hz Gsync monitor but the refresh rate keeps changing and is not stable, it keeps changing constantly to 50-80Hz happens to all of my games, and when a game has like 80 fps it keeps changing to 60-100Hz

tbowly
Member
tbowly

here’s the video of my problem: https://streamable.com/mm3oun

mustardpapi
Member
mustardpapi

I have a XL2546 so it is not G sync compatible. Should I still utilize 236 fps while using DYAC + nvidia V sync? Or are these settings G sync specific?

Alex UA6
Member
Alex UA6

Hey brother, my buddy, just picked up an LG ultra gear 165hz monitor with adaptive sync. I’m a little confused with the word adaptive sync. Is it just another word for free sync or G sync? I’m trying to understand if I should enable V sync when using adaptive sync. On my free sync display I enable V sync to eliminate screen tearing.

BNThuan
Member
BNThuan

Hi. Im playing ” crossfire” with monitor 165 hz . I setted up G sync “on” +V sync “on”+ limited fps “162” but in game fps still from 199-200 and lag. I have already changed setting NVCP but that problem has not improved. please give me advice. thanks

Karambol2K
Member
Karambol2K

Where did you cap fps? In game or in nvidia panel? I personally recommend RTSS for capping frames.

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