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.



2431 Comments For “G-SYNC 101”

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elexi
Member
elexi

Thanks for this Guide!
i already use gsync on + vsync on + 141 FPS LOCK on 144 hz screen.
some questions:
1) I often play VR games. Does Gsync + vsync combo somehow affect VR performance?
2) Is it combo good for Gsync-compatible screen, like mine LG UltraGear 27GL83A-B ?
3) And should i use LLM On or should i set in on AUTO (now i play with auto)? I mostly play non cybersport dx12/vulkan games
4) Does DSR DLDSR tech affect gsyncvsync combo and lag?

CorvusCorax
Member
CorvusCorax

I have read the entire guide. However, I have one question that is bothering me and I can’t find a reasonable answer anywhere. I have a monitor with a refresh rate of 240Hz, but I can’t use G-Sync. What happens if I set the frame limit to e.g. 100fps and turn on V-sync?

richardjohnsonfa
Member
richardjohnsonfa

If I have a amd gpu and freesync monitor, shall I follow your optimal settings but using freesync instead of g sync and amd chill fps limiter 3 fps under my monitors refresh rate instead of nvcp’s fps limiter. So it would essentially be freesync (using amd software) + v sync (using amd software or in game) + -3 fps below refresh rate limiter (using amd software, i.e. amd chill, or in game). Would it work the same as in your optimal settings? Thanks jorimt 🙂

Scandaal
Member
Scandaal

What do I need to set in the NVCP display settings if I use G Sync, I have an ASUS VG248QG 165HZ monitor.

At the moment I have No Scaling + Display set

Scandaal
Member
Scandaal

Hello I play WarZone 2 and I am interested in the G SYNC + V Sync setting, I currently have G Sync and V Sync enabled (In NVCP), also I enabled NVIDIA Reflex in the game settings and now my FPS is limited to 158fps (Monitor 165hz).

Can you tell me the optimal G Sync settings for this game, maybe there are better options to get optimal smoothness without frame tearing and micro staters

RTX 3060 / 12400 5Ghz / 3466 CL14

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