The new Avid Audio Engine had dramatically better support for handling processors with multiple cores. The new AAE also added a feature called Dynamic Plug-in Processing, where native plug-ins could be temporarily deactivated if Pro Tools detected they were not actually processing any signal. The new Avid Video Engine was apparently taken from Avid's video-editing program, Media Composer to try and improve the video workflows in post-production and reduce the amount of transcoding needed.
Pro Tools 11 implemented two new engines for handling video and audio.
