Microsoft is slowly rolling out the Fall Creators Update to Windows 10 users.
This update has a side-effect in OB of the viewports acting slow/sluggish and sometimes erratic in non-directx mode.
It's pretty hard to articulate the issue in words, so I created a video demonstrating the unwelcome effects of the Win10 FCU and that this issue would need to be investigated along with a compatibility update to Object Builder pushed out for Windows 10 users.