Turning off vertical sync doesn't have any effect

[hanspacket]

During some prototyping work, I wanted to compare the performance of GLWpfControl with my current approach for rendering OpenGL content in WPF. I would basically like to measure which approach has the biggest performance overhead. My intent is to open a large window, and compare framerates for both approaches. I don't want to add too much actual content so that the performance overhead is more prominent, so I'm painting a fairly lightweight scene using OpenGL.

This means that I end up with high framerates, even for fairly large windows (3840x1080 in my case, I can't seem to go beyond this size). To get proper FPS results, I disabled Vertical Sync in the NVidia control panel. This has the following effect:

• In the old approach, the framerate is not capped to 60 FPS anymore, and I get framerates of ~250
• Using GLWpfControl, the framerate remains capped at 60 FPS.

The second point is a bit unexpected for me since I didn't see anything in the GLWpfControl source code that indicates a fixed framerate. I might be wrong though.

Is this a bug ?
Is this a normal side-effect of the DirectX-OpenGL interop in GLWpfControl ?
Is the framerate capping something I can enable or disable some other way ?

Note that I'm using OpenTK.GLWpfControl version 3.3.0 since I'm using .Net Framework.

[NogginBops]

It does seem weird that the framerate is limited.
This might have something to do with the DX-OpenGL interop, but I'm not sure.
I'm not sure when I'll be able to look into this, especially the 3.3.0 version but I'll keep it on my todo.

[nasser225]

Hi @NogginBops , did you get anywhere with this? I am experiencing the same issue - 60FPS limited using GLWpfControl 4.1.0

[NogginBops]

I've not gotten to this issue yet. I'm planning a refactor of the DX interop part of this control and while doing that I can look into what the issue is here with vsync

[NogginBops]

My current guess for this is that WPF is limiting the framerate in their render thread. We are using D3DImage to display DirectX content in WPF and I guess that the refresh rate of that is locked to WPF in some way.