Testing video capturing by attaching directly to vesa framebuffer segment. The additional delay is most likely related to the entire screen image going back to devdraw as a new Image update, only to be redrawn in a window in the bottom right corner of the screen. Tearing is visible, which is caused by not having any kind of frame synchronization. Perhaps userspace devdraw with explicit synchronization (and maybe even transcoding) would be a better choice.