VSync stuttering without vsync being enabled

[thyslo]

Since about one year I have a WinUAE configuration that works fine on my Win10.

I don't remember changing anything substantially except temporarily playing around between 68030/68040 CPUs or adding a XBox game controller.

But some days ago I noticed some audio stuttering in the music of the game UFO. It is jittering and sounds as if it is played half speed.

I looked into speed issues and found that in fullscreen mode SysInfo reported only about half the speed as in windowed mode (PAL).

In WinUAE I have no vsync enabled but I have set the fullscreen setting to 720 x 576 and instead "Default refresh rate" I selected "50Hz PAL".

I did this because my display (Dell U2715H) allows to display 720 x 576 in 50Hz and I wanted PAL games to run smooth.

When I select "Default refresh rate" instead of "50Hz PAL" SysInfo shows the full speed in fullscreen mode and the speed issue is gone.

It seems that the 50Hz setting is introducing some vsync which causes the speed issue. Or did I misconfigure something?

[Toni Wilen]

Try double buffering. It is possible triple forces vsync depending on GPU settings. Forced vsync is not (and can't be) compatible with winuae.

[thyslo]

Thanks a lot, switching to "Double buffering" solved it