flood's input lag measurements

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Re: flood's input lag measurements

Post by Sparky » 21 Apr 2017, 03:39

br00m wrote:Thats interesting. Thank you so much. As I said in another post my specs are: i5 2320 HD 7850 and i get a constant 200 FPS on lowest setting. On the workshop map (https://steamcommunity.com/sharedfiles/ ... =500334237) i get 207.81 FPS on average. Did you upload it somewhere lex?
sounds like you might be GPU limited, so a framerate cap might decrease latency by a frame or two(5~10ms). use fps_max.

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Re: flood's input lag measurements

Post by br00m » 28 Apr 2017, 16:44

Thank you very much Lex. That would mean that the sluggish feel is there becasue of my hardware/settings. Also another thing: When you go in windowed mode in csgo and press the windows key so that the start pops up, you will get the windows cursor in addition to the csgo cursor. I notice a huge delay between those two cursors. I wonder if its because its windowed or if this delay is just in the menue and not it the game.

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Re: flood's input lag measurements

Post by RealNC » 29 Apr 2017, 01:04

Wait, you're playing in windowed mode? If you care about input lag, don't play in windowed mode.
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Re: flood's input lag measurements

Post by Chief Blur Buster » 29 Apr 2017, 01:15

Correct -- yes...

Windowed mode (including full screen "borderless" windowed) adds more lag than true fullscreen mode.

It's possible to greatly lower lag (e.g. VSYNC OFF in windowed mode) but it will still have more lag than the same setting during true fullscreen mode.
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Re: flood's input lag measurements

Post by Glide » 29 Apr 2017, 03:01

Does that still apply if you're using G-Sync in windowed mode?
I had always used fullscreen exclusive mode until I got a G-Sync monitor, and I have to admit that windowed mode is very convenient.

How does the new enhanced fullscreen mode in Win10 CU compare to true FSE Mode?

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Re: flood's input lag measurements

Post by RealNC » 29 Apr 2017, 04:22

G-sync windowed still has the DWM input lag. What you get is DWM being synced to the refresh rate. DWM still needs to copy the application's output to its own buffer and do compositing, which means at least 1 frame of input lag (maybe 2 if DWM uses tripple buffering; I don't think anyone tested.)

The new non-exclusive fullscreen mode actually does disable DWM (which why you can see tearing in that mode with vsync off and gsync off.) That means no additional input lag. This should be the same as windowed mode in Windows 7 and earlier with disabled desktop composition (like when using the "Basic" theme.)
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Re: flood's input lag measurements

Post by Glide » 29 Apr 2017, 05:08

I was afraid that would be the case.
It's so convenient to use windowed mode now that I've tried it...

Would I be right in thinking that Windowed Mode G-Sync would at least be lower latency than Fullscreen Mode V-Sync, even if there's an extra frame of lag vs Fullscreen G-Sync?

What about D3D12 / Vulkan?
As I understood it, neither of them have true fullscreen mode support.
Does that still mean you need to use "fullscreen" mode (which is the new enhanced fullscreen mode on Win10) or does borderless mode also have reduced latency?

I've noticed that games using the new enhanced fullscreen mode will tear if you disable v-sync in borderless mode, which seems to suggest that both modes may be bypassing the DWM now.

To check if a game is using the new enhanced fullscreen mode or not, hit Win+G and see if it brings up the game bar.
If the screen flashes twice instead of bringing up the game bar, it's using the old fullscreen mode.
If the game bar appears, it's using the new enhanced fullscreen mode.
This can be disabled via the compatibility options for the executable if you want the old FSE/Borderless behavior back.

I wonder if there's a way to force games to use the enhanced fullscreen mode, as it currently only works with games that Microsoft has whitelisted.
This is the most complete list that I have found so far.

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Re: flood's input lag measurements

Post by RealNC » 29 Apr 2017, 05:18

Glide wrote:Would I be right in thinking that Windowed Mode G-Sync would at least be lower latency than Fullscreen Mode V-Sync, even if there's an extra frame of lag vs Fullscreen G-Sync?
Yes, that's true. Windowed mode vsync is the worst of the lot, since you get BOTH the vsync lag as well as the DWM lag. G-Sync rules still apply though: you need to cap the framerate below the refresh rate to avoid vsync lag in windowed mode too.
What about D3D12 / Vulkan?
As I understood it, neither of them have true fullscreen mode support.
Does that still mean you need to use "fullscreen" mode (which is the new enhanced fullscreen mode on Win10) or does borderless mode also have reduced latency?
They are a weird mix of fullscreen and borderless. No DWM lag, that's disabled.

Basically, if you can switch resolution, it's not really windowed mode. In windowed mode, you run at the desktop's resolution.

This new "non-exclusive fullscreen" mode is actually quite awesome, when you think about it. No input lag, but still faster alt+tabbing compared to exclusive, and you can still switch resolution, and your color settings are followed (I think.)
I wonder if there's a way to force games to use the enhanced fullscreen mode, as it currently only works with games that Microsoft has whitelisted.
This is the most complete list that I have found so far.
I'm not aware of a way, sadly. It seems OpenGL games also use this mode though. No Man's Sky for example came out in summer last year, but it was using this new mode too when selecting "borderless windowed." And that's on non-Creators-Update Windows. Which is weird. I'm not sure what's going on there. I suspect the driver can put the game in that mode automatically (at least on nvidia), but it doesn't do that for DirectX games.
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Re: flood's input lag measurements

Post by Glide » 29 Apr 2017, 05:29

RealNC wrote:This new "non-exclusive fullscreen" mode is actually quite awesome, when you think about it. No input lag, but still faster alt+tabbing compared to exclusive, and you can still switch resolution, and your color settings are followed (I think.)
So does that mean games running in the new borderless mode are also free of DWM lag, since that also allows for screen tearing?
As I understand it, you should still get all the latency benefits so long as nothing is overlaying the window.
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Glide wrote:I wonder if there's a way to force games to use the enhanced fullscreen mode, as it currently only works with games that Microsoft has whitelisted.
This is the most complete list that I have found so far.
I'm not aware of a way, sadly. It seems OpenGL games also use this mode though. No Man's Sky for example came out in summer last year, but it was using this new mode too when selecting "borderless windowed." Which is weird. I'm not sure what's going on there. I suspect the driver can put the game in that mode automatically (at least on nvidia), but it doesn't do that for DirectX games.
Microsoft have been working to move all "legacy APIs" over to using the new DWM mode - though I was not aware that it (apparently) included OpenGL.
Anything DX9 or older uses it by default.
It only seems to be DX10/11 games that have to be whitelisted to use it.
I was hoping that someone might have found a registry key where other games could be added to the whitelist for example.

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Re: flood's input lag measurements

Post by RealNC » 29 Apr 2017, 06:02

Glide wrote:So does that mean games running in the new borderless mode are also free of DWM lag, since that also allows for screen tearing?
As I understand it, you should still get all the latency benefits so long as nothing is overlaying the window.
Yeah. As soon as an overlay needs to be displayed (like the volume indicator), DWM is activated. When the overlay goes away, DWM is turned off again.
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