Separate table by often changed / not often changed data?
Yes, it will make a difference.  How big a difference will depend both on how many rows the table has and how many columns as well as how frequently the table is read from and updated.  Depending on the database, the block size and how many rows are updated at the same time could also be factors.  

Keep in mind the overhead you are introducing by splitting the table for how often the data will be queried separately vs how often it will need to be joined and the performance requirements of various reading and writing activities.