Well, wanted to provide an update and hoping someone may know a solution or the cause.

I have taken a Blank 2013 document and added 15 OLE Links to tables in an excel file. That word file now takes about 1 minute to open. I am also asked to save that file even though all I did was open it only, with no changes made.

But if I downgrade that file as a .doc extension, the file opens almost immediately. And I am not prompted to save the file by just opening and making no changes.

I can see when the file is saved as a .docx file, that Word is actually, opening and reading the excel file for each link in the background. However in the Word Advanced options, I do have "Allow automatic links at open" unchecked/disabled. And I also have all links set for a Manual update vs. automatic.

An example of one of these links looks like as follows.
Edit.
I'm reading what I can but have not come across a fix yet. It appears this issue has been around since at least Office 2010.
https://social.technet.microsoft.com...s-is-very-slow
http://support.microsoft.com/kb/2504009

Now 4 years later, and using Office 2013, it seems this issue is still around.