I do NOT know if this is at all related, and may be a completely new set of issues with ST3, but even with ST3's VST3 version out of the picture, I cannot get ST3 to allow me to select ASIO as a driver mode in its options.
 
As soon as I click on ASIO, instead of Windows Direct (I think that is the name), ST3 simply hangs (this is running ST3 in stand-alone mode).  I have to actually pull up Task Manager to kill it.
 
Bob Bone

I DO have to say, running ST3 inside a Sonar Platinum project - with the VST3 plugin renamed, it works just fine - the issues I raised in my earlier post were ONLY when trying to run it in ASIO driver mode.
 
Bob Bone
 

Try adjusting your audio card's buffer setting.

Early VST3 versions of ST3 caused problems for me.  However, later versions are rock solid here.
 
Perhaps you experienced some corruption during the crashes you were having.  I would completely uninstall/reinstall ST3 (including VST3) and see if maybe things are stable.