Case is simple, the game uses 32 bit version of the system so it has limitations to ram, which causes crashes.

You have to download a simple program which upgrade saintsrow4.exe to x64
Link: https://www.dropbox.com/s/whatdgv804h8pjl/4gb_patch.exe?dl=0

Put this file in the game files and start the process
Find the SaintsRow4.exe and end update.

With this my game didn't crash ONCE, so I hope you will enjoy the game without the problems. ENJOY

P.S.
This program works with a lot of games so if you find similar problems with other games you can try using this.