Crashing in maps

For some reason my game crashing in the middle of maps and only maps, ive played for over 100 hours getting my char to lvl 80 and jsut started mapping, every 2 maps my game crashes and this has never happened before
i7-4770 CPU
AMD Radeon(TM) R9 270X
8GB RAM

I also got radeon R9 200 serie and i getting error message sometime when i use portal back to my hideout? very annoing to have to make new zombies and shit