Noticed some differences between borderless fullscreen and windowed mode.

[Xavvy]

As the title says I have noticed some stark difference between borderless fullscreen and windowed mode.. For whatever reason windowed mode is more stable overall(windows 11.. maybe windows version changes things)than borderless fullscreen or windowed fullscreen(In some games I have noticed borderless doesn't work but windowed fullscreen does and vice versa)

Playing on my RTX 4080 laptop it has a 2k 165hz screen, I use DLDSR 4k for everything(it looks gorgeous on an 18" display).. I use x3 mode.. and was using borderless fullscreen and having LS1 used at a factor of 1.5 for great performance and still very high visual quality. In some games this is fine but in most games I lose image stability and max interpolated frame rate(base is unaffected but I seem to lose some of the interpolated frames i.e base 55fps and instead of seeing 165fps .. I will see like 130-165 fluctuating..

The moment i switch this from borderless/windowed fullscreen methods to a windowed mode set a certain resolution(2560x1440 because it equals factor 1.5 @ DLDSR 4K) all that image instability and lost interpolated frames disappear.. my interpolated top end remains stapled at 165 and my base is also just as stable if not more stable..

I don't care that this happens, it's a none issue. setting every game to windowed 2K resolution is just as easy.. I'm just curious why these issues happen in windowed fullscreen modes.. anyone know?

[Spook]

Originally posted by Xavvy:

As the title says [...] anyone know?

Interpolating 4k is nearly twice as costly as interpolating 2k. This is at x2, x3 might exaggerate this. It appears you a creating headroom by lowering the games output resolution and thus the size of frame that LSFG has to process.

For performance reasons i highly recommend you use minimal upscaling in the game (DLSS Quality or DLAA, no lower) and lower your game's resolution/window size instead, as this lower the performance cost of LSFG. Especially at 4k.

You will also likely get a sharper image using 2k native. At DLDSR 4k with a scale factor of 1.5 you are effectively rendering 1440p with extra steps. Probably meaning extra performance overhead and a worse image quality.

That's not to say using DSR/DLDSR/VSR with LS is useless. I use it to upscale games from 1.3-7 times 4k to 8k DSR. Resulting in stupid clean and sharp edges/details. It gets really costly past 4k though, framegen that is.

[Spook]

Other possible factors;

-Some games don't allow LS to scale down their borderless fullscreen window, effectively ignoring your scale factor causing you to still be rendering at 4k.

-This one's a stretch, but; Windowed mode is causing Window's "Optimizations for windowed games" to kick in, gaining you performance somehow. Good thing is you can test this one by disabling/enabling these optimizations on a per game basis in the Windows "Graphics settings" menu.

[Spook]

You can also eliminate a factor by setting your desktop resolution to DLDSR and letting LS change your game's windowed resolution with scale factor, if the game allows.

Since a DLDSR 4k resolution @ 18in screen size might make things hard to see, you could use "Hotkey Resolution Changer" to change resolutions without a hassle. Works with DSR.

[Xavvy]

I've figured it out. It's a few things. One of them being weird change in behaviour in how border-less/windowed full-screen scale in certain games. I noticed anything DirectX12/Vulkan seemed fine, anything DirectX11 or lower/OpenGL came with possible scaling issues. Sometimes you can bypass this issue in some games by running windowed at a resolution very near native. or by running a scaling factor like reduction and then obviously just using 'Auto' mode.

Also there were a few DirectX12 games I tested that had minor issues. So it can also be game engine specific(which is probably more than likely going to be the average cause most likely, my tests were fairly anecdotal as I only tested a dozen or so games). Interestingly enough windowed optimisations holds up quite well. I know since Windows 11 that Border-less/Windowed Full-screen come with the same performance now(except in some VERY older titles) as exclusive, so there is little to no reason to run Exclusive Full-screen anymore except for older game emulation in compatibility modes.

When doing tests comparing windowed to border-less at the same factor rate the performance of windowed mode holds up and in some cases was slightly better than border-less/windowed full-screen(some modern titles seem well optimised for window gaming). So yeah.. that's interesting.. But yeah in my tests it's pretty conclusive, if scaling from a full-screen window of any kind causes issues or has a sort of delayed/stuttering/hitching response, you can almost be certain that once it settles it's going to cause hitching/stuttering/bad frame pacing/top end interpolation loss when using custom scaling on resize(which if the game supports it properly is the way to go)

In my tests I found something interesting. border-less/windowed full-screen @ 4K at a 1.5(2K) factor appears to have an almost down-scaled approach on it's custom factor resize that nets you superior image quality while also having better performance to 2K up-scaling to 4k.. 2K auto up-scaling to 4K costs a whincey bit more(it's not major, something like 2-4% more usage) but has a very slightly less image quality(it's not major.. but like it's a whincey bit noticeable when I take comparison screen-shots.

So yeah the final test results conclude.. If a game supports custom scale factor down-scaling with resize on border-less/windowed full-screen, that it's best to do it this way.. it will result in slightly better image quality for slightly better performance.. but it seems a lot of DirectX11 engine'd games have issue with stability doing this. So be prepared to set resolution for a upscaled factor rather than using the custom scaler in some games if you want proper stability/performance.

[Spook]

Originally posted by Xavvy:

I've figured it out. [...] stability/performance.

Thank you, interesting.

Also, are you really really sure that 4k DLDSR in borderless fullscreen mode isn't just straight up outputting 4k DLDSR, regardless of scale factor? Because if i set FH5 to 8k DSR in borderless fullscreen mode it straight up ignores my set scale factor and performance tanks.

Scaling window size down with scale factor on an 8k desktop works as fine and changes sharpness and GPU usage accordingly.

Also, you might want to look into Hardware Accelerated Scheduling, has been a stutter-causing headache for many 4090 users.

[Xavvy]

Also tested this in a few games that allow you to switch between DirectX11 and 12. In all games DirectX12 removed the issues with scaling/hitching on frame pacing/top end interpolation loss. It just sucks because some games run better in DX11 than they do DX12(cough.. Borderlands 3 hitches on most machines in DX12 more than it does in DX11 and gains no benefit from DX12 graphically or in any way shape or form..not really sure why they added it.

Anyways. Yeah everything you said. I already knew.. I appreciate you trying to help. I only ever use DLDSR or DSR on desktop mode(it's the best way to use it if you can get the values right). if you get the smoothness to the right value depending on resolution/screen size/type it works flawlessly and with spatial scaling/up-scaling in games I fail to not why people wouldn't use it given the option. Especially in the case of DLDSR.. It's basically super efficient image quality enhancement/anti aliasing when you use it with a spatial up-scaler/proprietary up-scaler in games.

In my opinion. DLDSR+DLSS Quality is better looking that native by a long shot because of the double high refine TAA passes built in.

[Xavvy]

Originally posted by Spook:

Originally posted by Xavvy:

I've figured it out. [...] stability/performance.

Thank you, interesting.

Also, are you really really sure that 4k DLDSR in borderless fullscreen mode isn't just straight up outputting 4k DLDSR, regardless of scale factor? Because if i set FH5 to 8k DSR in borderless fullscreen mode it straight up ignores my set scale factor and performance tanks.

Scaling window size down with scale factor on an 8k desktop works as fine and changes sharpness and GPU usage accordingly.

Also, you might want to look into Hardware Accelerated Scheduling, has been a stutter-causing headache for many 4090 users.

I'm positive. I know when games are just straight outputting because I use an RTSS Stats overlay(it comes in a set size that you set so if a game isn't outputting it's easy to tell.. besides the not so obvious image quality change on an only 18" screen.. that RTSS blerp of stats changes in size dramatically making it easy to spot when a game doesn't behave right with borderless/windowed fullscreen. I'm aware of the 4090 issue as well. My desktop rig has one and it's annoying af but I found a few work arounds.

Edit: Also if a game is not scaling from borderless/windowed fullscreen when desktop is set to DLDSR factor.. that's the game not a DLDSR issue. DLDSR is replacing your desktop resolution. As long as you have scaling set in GPU drivers correctly. That will never be an issue. This issue is game engine based. It's really annoying but yeah. A lot of game engines are trash at proper on the fly scale changing. I noticed an issue as well with DLDSR, high dpi scaling behaviour and certain borderless/windowed fullscreen methods. So in some game it works if you either turn that on or off in the properties of the games executable.

[Spook]

Originally posted by Xavvy:

I'm positive [...] work arounds.