Need help confirming normal behavior with VRR in borderless windowed

[DominoFrancisco]

After some finagling with Nvidia drivers (using DDU to remove and go back to 566.36) and a windows upgrade to 24H2 I found out that I had inadvertently disabled multi-plane overlay on my two monitor setup somehow this whole time.

Before this, while running a game in borderless windowed mode and G-Sync Compatible enabled, the monitor would report the correct refresh rate while the game was focused and any time I alt-tabbed or clicked over to my second monitor, the refresh rate would return to the normal 180hz. After these updates and driver changes, I noticed that any Explorer or web browser windows on either monitor are affected by the frame rate of the game that's running.

I just want to be sure, is this normal behavior, for a game to be affecting DWM framerate now that MPO is confirmed through SpecialK to be working properly? Did I just get used to how borderless windowed games function without MPO? And is it normal behavior for only one monitor to support MPO at a time?

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[RealNC]

AMD drivers can do MPO on both monitors. Nvidia only on one, regardless of how many MPOs the GPU supports. Also, the monitor that gets the MPOs seems be quite random.

Another thing is that forcing vsync globally in NVCP can result in DWM getting g-synced by random apps or games. Because of that it's always best to leave global vsync set to "3D application preference". If you need to force v-sync, either use the per-application profile, or force it in SpecialK.

In any event, you don't actually need MPOs for games running in windowed mode to be able to use g-sync, unless you're using some kind of overlay like Windows Game Bar or the new Discord overlay. Discord in particular will prevent flip model presentation (and thus g-sync) from working even when the overlay is not visible. You can verify which presentation model is used in SK's UI in-game. "Independent flip" models allow g-sync to work and have lower latency. Anything else means g-sync can't work and there might be DWM latency.

[DominoFrancisco]

AMD drivers can do MPO on both monitors. Nvidia only on one, regardless of how many MPOs the GPU supports. Also, the monitor that gets the MPOs seems be quite random.

Yeah thankfully I confirmed with SpecialK that my main monitor is the one with working MPOs.

Another thing is that forcing vsync globally in NVCP can result in DWM getting g-synced by random apps or games. Because of that it's always best to leave global vsync set to "3D application preference". If you need to force v-sync, either use the per-application profile, or force it in SpecialK.

In any event, you don't actually need MPOs for games running in windowed mode to be able to use g-sync, unless you're using some kind of overlay like Windows Game Bar or the new Discord overlay. Discord in particular will prevent flip model presentation (and thus g-sync) from working even when the overlay is not visible. You can verify which presentation model is used in SK's UI in-game. "Independent flip" models allow g-sync to work and have lower latency. Anything else means g-sync can't work and there might be DWM latency.

Yeah I actually left the vsync setting to application preference from the beginning. The gsync itself is working fine and I've used SpecialK to confirm it between multiple games. I can actually tell a huge difference from earlier, on newer drivers, where it must not have been working correctly or MPOs werent active.

The thing I'm not sure of is why things like Windows Explorer and my Firefox windows are getting affected by the GAME'S framerate. For instance if I change the frame rate cap in Final Fantasy XIV between 60 and 30 FPS, or I let the game's idle framerate limiter kick in, it will lower the framerate of those windows too. Is this normal behavior with working MPOs?

[RealNC]

The thing I'm not sure of is why things like Windows Explorer and my Firefox windows are getting affected by the GAME'S framerate. For instance if I change the frame rate cap in Final Fantasy XIV between 60 and 30 FPS, or I let the game's idle framerate limiter kick in, it will lower the framerate of those windows too. Is this normal behavior with working MPOs?

Only if the game is focused. If you alt+tab to another window, then that window controls VRR, or VRR is disengaged if it's not a game.

Multi-monitor setups are still wonky though, especially with VRR.

[DominoFrancisco]

Only if the game is focused. If you alt+tab to another window, then that window controls VRR, or VRR is disengaged if it's not a game.

Multi-monitor setups are still wonky though, especially with VRR.

Yeah, very odd. It still does it even when the game has been absolutely unfocused, and even with only one monitor active. The only other thing I can think of is this may be a quirk of these older drivers in particular. I specifically removed the newer ones and installed the December 2024 drivers because of how many issues the newer ones have been causing across the board. Might as well try the newer ones again and see if it fixes it.

[RealNC]

Yeah, very odd. It still does it even when the game has been absolutely unfocused, and even with only one monitor active. The only other thing I can think of is this may be a quirk of these older drivers in particular. I specifically removed the newer ones and installed the December 2024 drivers because of how many issues the newer ones have been causing across the board. Might as well try the newer ones again and see if it fixes it.

I'm on 566.36 myself and never seen this happen. Last thing I can think of is that the VRR setting in Windows itself might be affecting this. Try turning it off/on and see if it makes a difference.

[DominoFrancisco]

I'm on 566.36 myself and never seen this happen. Last thing I can think of is that the VRR setting in Windows itself might be affecting this. Try turning it off/on and see if it makes a difference.

Yep that was it. Issue goes away when the VRR setting in windows is set to off. Flipping it off and on again had no effect. PresentMon still showing hardware: independent flip even after alt+tabbing. Can't believe that eluded me the whole time, lol. I appreciate the help.