I"m having issues with slow zooming in N5. When you hold down the zoom key it acts like there are several detentes in the range. Very jittery. Takes forever to zoom. When you zoom in the time bar (“Zoom while Locating in Time Scale”) its fine. Speedy. Smooth. I’ve never experienced this issue on my PC with Nuendo 2 - 5. The 5.5 update has not resolved the issue.