Dual monitor crash after update

Hi, i'm writing here because since last update i had been started having a lot of crash problems. I have a high end pc (4770k + 7970 ghz edition) playing in dual monitor configurations, with 1 monitor in 1440p borderless and the other one just used for TS, internt ecc, and i never had a single slowing on FPS in game in 9 monhts of continous playtime, but from last update sometimes the game just freeze in the crowdy zone and then or re-start or just crash...and the strange thing is that ONLY the game freeze, the other monitor is perfecly usable, no problems, nothing!! I tried playing 2 character from the same pc, 1 borderless on main screen 1 in window mode on the other monitor (i used my wife's character to do the test), then i went to an hunt with BOTH character (i remeber, RUNNING IN DUAL BOT FROM THE SAME PC!!) and the borderless window one CRASHED, the other one NO!! it's really really strange!! Do you have any idea to solve the problem? it's really annoying because i'm losing a lot of alliance point :/

P.s. in dungeon or ot crowdy area it doesn't happen!!
p.s.2 i didn't changed video driver or anything on pc, the starting point of the problem is only the update moment ;_;