When trying to digitize by SDI, I keep getting this error, "Capture aborted due to video overrun."  This happens every couple of minutes. 

Any insight on how to resolve?

 Are you running a qualified graphics card? Do you have enought RAM on your system?

video overrun usually means that your system (ore at least one vital component) is not keeping up with the incoming rates.. Post specs like version Avid, version OS, version Nvidia drivers and system related specs as memory, drives etc..

Menno

 Yes, that can very well account for the system response time and performance to suffer. It tasks the system with that many more files to go through and manage in real time. Especially when you go over 85%.  It gets to be like trying to stuff 20 pounds of potatoes into a 5 pound sack - something's going to give somewhere.  I'd cull out as many projects, media and precomputes you can to give yourself some head room on your raid.