Okay, i think i got it because it works for me. First of all i went to my savefiles -> check properties from all files and delete all files bigger than 6,8mb. Everything over 7mb is corrupted and you'll get 5min loading times and crashes/freezes.

Then i used this method here: http://larian.com/forums/ubbthreads.php?ubb=showflat&Number=605573 with my latest savefile that is between 6 - 6,8mb that is not corrupted.

Ingame dont use quicksave. always save manually and dont overwrite them. always use a new one.

This method is just temporary. That means you can play for like 2-3 hours befor it gets corrupted again. Every now and then again to your savefiles and check your latest file if its over 7mb or already 8mb. IF SO: delete them, use the method again and play again for few hours.

It works for me, maybe it'll work for you.