[Zubersoft]

If you tap the circle at the top left corner of the annotations editor, is "Draw highlights behind content" enabled? If so, that can cause considerable slowdown during rendering as it has to perform some of the rendering without hardware acceleration. Let me know if you want the reason behind that, but it's pretty involved and has to do with pixel blending and how the hardware accelerated graphics work in the Android rendering framework. One thing I can do to speed up the rendering (which I did for e-ink devices and older Android devices), is to only draw the highlights behind the page content when the user isn't actively annotating (meaning a finger or stylus isn't touching the screen). That may be why your Samsung Galaxy Note 2014 doesn't have the issue.

If that isn't the cause of the slowdown, let me know. That would indicate something else is going on.

Thanks,
Mike