Lots of new and old MBP models. Which one?
Apple Menu (top far left)>About This Mac>More Information> look at the attachment... specifically Model Identifier ( I have an older MacBook Pro6,2)
What is you I/O buffer setting in Logic preferences>Audio>Devices???
Small I/0 for tracking, large buffer when mixing with lots of plug-ins.
Does the overload occur with a small vs large I/O?
The next thing to do is quit Logic, turn off your monitors, then turn off your interface.
In the AudioMIDI Utility, select the Built-in Output. Open Logic, then in Preferences, select the Built-in Output option.
Play some heavy mixes. Any problems?
If not, then enter the following into the search engine of your choice: your specific MBP model, Presonus Fireface 800, firewire overload.
See what comes up.