Does this cause any performance decrease? I swear after doing this, my performance has dropped a bit. Nothing earth shattering, but I'm limited by mainthread now which wasn't an issue prior. 

Aaaaaaahhhhh what back at you.  Please bear in mind that I don't know much about you or your experience - all I have to go on is what you share with me.   Bottom line is if the Captain Sim product works there is no reason the Airbus Professional shouldn't work.  My advice would be to uninstall and reinstall the latest version, insuring computer security is disabled during the installation process and the installer is run as Admin.  After installing the latest version, please start P3D, load the aircraft and then close P3D. Then reboot and run the ASUpdater or Aerosoft One Client (I don't know if the Airbus Professional uses the Aerosoft One Client for updating yet).   Let me know how you make out!        

Tried the workaround on both the 550 and 700 and pleased to report both worked well. Speed indication very smooth. Thanks.

same issue/ reinstall did nothing  

Yeah I know..