Apart from higher configuration, Efficiency depends on better synchronization among hardware and memory management. With optimizing free spaces, user can avail faster speed.
In-fact, OLM file is not compatible with Outlook 2013. That's why, user is bounded to convert OLM file into PST file. Then, PST file can be imported into MS Outlook 2013 directly.
I found a similar reference, mentioned below:
https://discussions.apple.com/message/27428787#27428787