Disabling VSync causes memory leak

[loneShade221]

Godot version

4.0.3 stable (applies to 4.0.1 stable, and 4.0.2 stable as well)

System information

Windows 7, AMD Athlon X4 860 Quad Core Processor, AMD Radeon R7 250 Series

Issue description

Disabling VSync in the Project Settings (as well as in GDScript) sometimes causes a ~60-80 kB/second memory leak, as observed in the Windows Task Manager. The leak happens after running the application for about 10 seconds, after which the memory leak will endlessly pile on, without it being noticed in any of the Godot monitors.
This happens with the Forward+ renderer, the others don't seem to have this issue.

Steps to reproduce

-Run the Windows Task Manager,
-Make sure that the project uses the Forward+ renderer
-Disable VSync in the Project Settings (or GDScript with the DisplayServer.window_set_vsync_mode(DisplayServer.VSYNC_DISABLED); line.)
-Run the your application by clicking the Run Project button,
-Wait for about 10-15 seconds, after which the leak will begin

Minimal reproduction project

Any project will do, simply add a new Node2D, disable VSync, and run the project.

[AThousandShips]

Shouldn't it be something other than DisplayServer.VSYNC_DISABLED

[loneShade221]

My bad, I typed Enable instead of Disabled.

[AThousandShips]

Cannot confirm on latest version

[loneShade221]

Do you have any idea why this might happen? It's a pretty big issue for me:

This scene is just a Node2D. Maybe it has something to do with drivers?

[AThousandShips]

Updating your drivers is always a good idea to eliminate problems, this could be a Win7 specific issue, as I am on Win11 and unable to replicate this issue

[Calinou]

The fact that disabling V-Sync causes a memory leak is more that uncapping the framerate causes the engine to render far more frames, making memory leak much faster. You can confirm this by leaving V-Sync disabled but setting the Max FPS advanced project setting to 60.

[loneShade221]

Yes, I have noticed that while I was doing some more testing on this issue. I updated my drivers, though it still didn't fix the issue, and the memory leak, although slower when the FPS is capped, is still there, and will eventually eat up memory completely. I didn't bother much with it after this, I simply enabled VSync and left it at that. Since the issue cannot be replicated on later Windows versions, this might be a Win7 limitation with Godot.

[Calinou]

Vulkan on Windows 7 tends to have various issues not found on more recent Windows versions. Given you're also on an old GPU (GCN 2.0 GPUs only have partial Direct3D 12 support for instance), it's best to stick to the Compatibility rendering method there.

[loneShade221]

Yeah, I understand, thank you informing me. 👍