DO NOT check boost priority. It should not be enabled and can lead to OS instability if it is enabled.

Max server memory should be set. See chapter 4 of https://www.simple-talk.com/books/sql-books/troubleshooting-sql-server-a-guide-for-the-accidental-dba/ for a sensible starting point. That book may also give you avenues of troubleshooting when the problem occurs. I can't tell from the description what might be wrong.