Windows 10 FullScreen Exclusive Optimization

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Windows 10 FullScreen Exclusive Optimization

Post by MonarchX » 17 Jan 2019, 17:29

I hope Blur Busters guru's know what it is and what it does, because I couldn't find a good explanation about it anywhere online. It exists only for Windows 10 versions 1709-15063 (Spring Creator's Update, RS2, I think) and newer. It definitely makes activation of Exclusive Fullscreen mode quicker/snappier, but people report:
- it causes stutters
- it's an additional overlay
- it not true Fullscreen Exclusive mode

I had some issues when it was first introduced in 1709-15063 and stuck to Win10 1607 for a while, but I think MS improved it in 1809-17763 (RS5). I moved from Win10 1607-14393 LTSB to Win10 1809-17763 LTSC recently and not looking back.

I also recall Blur Busters review/explanation of G-Sync results of either FullScreen Mode or Borderless test, where input lag was reduced in Win10 1709 compared to 1607. I'll link to it if If I find it...

For those who want it disabled without having to go through every .exe compatibility mode attributes, you can use this WMI script I got from MyDigitalLife forums that auto-disables FullScreen Optimization mode for every .exe launched a single time. That means it disables FSE when you launch the same .exe the second time - ... sp=sharing .

I personally do not use that script and enjoy FSE in 1809-17763, but I also eradicate Game Mode, Xbox-stuff, and most importantly get rid of Windows game detection by using NTLite to erase them (2 controlling items - Xbox component and Media Game Explorer components, NTLite free version removes them). Microsoft also has this KnownGameList.bin file that attaches itself to explorer.exe and must be removed with tricks from main Windows\GameDVR and UserName\AppData\Roaming\Microsoft\Windows\GameDVR directories. I was never able to decrypt/decipher that file.

So what do BlurBusters know about FSE? Does it relate to that GameKnownList.bin file? Does it all have any effect on G-Sync/V-Sync motion smoothness?

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Re: Windows 10 FullScreen Exclusive Optimization

Post by jorimt » 17 Jan 2019, 17:54

As a disclaimer, these are my casual, personal observations, which means they could very well be subject to inaccuracies (actual testing would be required), but from what I can tell about the most recent functionality of "fullscreen optimizations":

1. It's a hybrid borderless/exclusive fullscreen mode that is suppose to have the benefits of both.
2. It's set to on at default, so any game that is set to exclusive fullscreen mode uses this hybrid functionality unless disabled per exe. It's also possible that there is an invisible whitelist of supported games, because I've noticed it doesn't apply to every game I've played in exclusive fullscreen mode, even with the option on (still a slow alt + tab with black flash to desktop).
3. It's been my observation that DX9 games and under (and perhaps OpenGL games?) in the latest version of Windows 10 only support G-SYNC functionality when set to exclusive fullscreen IF fullscreen optimizations are left enabled in the exe. If not, G-SYNC will only work in borderless/windowed mode.
4. Disabling/enabling fullscreen optimizations for borderless/windowed mode + G-SYNC doesn't seem to affect anything other than DPI scaling settings in some games.
5. Unity engine has strange compatibility issues with G-SYNC, and depending on the engine version, G-SYNC will only function with exclusive fullscreen IF fullscreen optimizations are left enabled in the exe, even in DX11 games and up.

As for frametime performance differences between exclusive fullscreen + fullscreen optimizations off + G-SYNC vs. exclusive fullscreen + fullscreen optimizations on + G-SYNC, it could be my imagination, but the hybrid mode does seem to have more sporadic framepacing in certain games (microstutter) than when the option is off. But since I haven't done any actual tests, it's basically my perception at this point, so, grain of salt.

That said, I disable it per exe (for DX11+ games; again, it has to stay enabled for G-SYNC to work in older games featuring DX9 and under, at least in the DX9 games I have played) to be safe.

Finally, I did some off-the-record game mode/fullscreen optimization tests when originally writing G-SYNC 101:

While it didn't show any increase in input lag with it enabled, and I doubt it has an increase now, Microsoft has seemed to tweak the functionality since, and my testing method for input lag would not have picked up any frametime performance differences (microstutter), so that point is still up in the air.

It's currently an enigmatic setting, to be sure.
Author: Blur Busters "G-SYNC 101" Series

Display: Acer Predator XB271HU OS: Windows 10 Pro MB: ASUS ROG Maximus X Hero CPU: i7-8700k GPU: EVGA GTX 1080 Ti FTW3 RAM: 32GB G.SKILL TridentZ @3200MHz

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Re: Windows 10 FullScreen Exclusive Optimization

Post by MonarchX » 18 Jan 2019, 16:42

Thanks! This forum and you are a great source of knowledge! As far as FSE goes, I noticed that some DirectX 11 games, like Far Cry 5, simply will not launch with it disabled, while other games, such as Grim Dawn, at least in the past, would refuse to launch with FSE disabled if ReShade was present.

But it also does something with the mouse movement. Mouse doesn't feel the same with FSE. It kind of... glides, even on desktop, even with same exact acceleration-removing tweaks I apply in earlier pre-FSE builds, in which mouse didn't glide that way. It's very hard to explain, I don't know how to objectively explain "mouse gliding feel" of FSE.

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Re: Windows 10 FullScreen Exclusive Optimization

Post by MonarchX » 01 Feb 2019, 21:53

I came across an interesting Reddit reply on this topic and it had a link to some education material you might be interested in:
D3D12 doesn't allow exclusive fullscreen at all, all D3D12 programs with fullscreen are required to use a borderless window mode.

It's not as bad as you'd think though, because of things that have been happening in Windows since 8.

Windows 8 introduced the 'flip' presentation mode, which allows the desktop compositor to directly use the same buffers as the application, instead of needing to copy the window's display into an extra internal buffer. MS also required use of this mode for windows store apps, which at the time were always (borderless window, since the compositor was still running) fullscreen.

So they also added an an optimized mode ('dFlip') that allows the compositor to give away some level of control when there's a fullscreen windowed application using a flip mode.

Windows 8.1 added an enhanced mode ('iFlip') that has lower latency (getting down to <1 frame when the app has vsync off, and just under 2 in 'normal' vsync), and also added a new API for 'low latency' vsync that cuts a frame off vsync latency (getting down to just under 1 frame in fullscreen).

Windows 10 + D3D12 allows another mode ('iFlip Immediate'), which requires vsync off, but is otherwise as performant as exclusive fullscreen.

For some more detailed technical information, Microsoft has a video on the different possible modes in Windows 10 as part of their D3D12 education set - .

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Re: Windows 10 FullScreen Exclusive Optimization

Post by drunkencats » 04 Feb 2019, 20:06

Hey monarchX, i have read a lot of your posts on numerous sites and they helped me a lot.
I tried to disable gameknowlist.bin with unlocker like you did but for me it didnt work. But i have found that if a i use the two scripts disable_gamebarpresencewriter and automatically_disable_fullscreen_optimizations made by aveyo on fresh installed windows 1809 the games will run on exclusive fullscreen, but only works if you run the scripts before running any games. Perhaps this information can have some use for you.

Thanks a lot and sorry for my english.

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