Hi there,
Pro Tools along with other Audio recording software can sometimes have issues with multi-core CPU's and or Hyperthreading, hence the reason that it is sometimes recommended to disable this feature, especially f you find that you are having issues when recording multi-track audio or when using lots of VST plug-ins etc.
To disable Hyperthreading on your motherboard you need to go to the M.I.T. section of BIOS and then Advanced CPU Features. Just a note from the User's Manual that says: This item is only present if you install CPU that supports this feature.