Multitasking does help a lot with MVTools. If you use it for HD conversions using X264 or X265 you might get crashes sooner or later. AVStoDVD seems to be less affected in my experience.
My plugin package for AVStoDVD now also has a section on using AVS+ MT under AVStoDVD. Download here:
https://files.videohelp.com/u/172211...D%20Plugins.7z
Cheers
manolito