Constant freezes after update to latest windows 10

Jun 2, 2018
Last day I've upgrade my PC to windows fall creators update using clear installation from usb stick (created by media creation tool). Yestarday everything seemed to work fine, but when I booted my Pc today the computer was freezing (nothing moves on display) every 1 second. Later I've discovered that it happens only when my second monitor is off. If both of my monitors are on - there are no freezes. If I disable second monitor in windows settings (only display 2) freezes also disapears. Later I've swaped the cables, so my main monitor is indexed as [1] and second [2] and there were no freezes on monitor 1, but there were on 2.

Because it can be very confusing I will write everything one more time using a table:

monitor 1 on    monitor 2 on   freezes on monitor 1    freezes on monitor 2
true               true              no                     no
true               false             no                     -
false              true              -                     yes
No matter which monitor is marked as 1 and 2 in windows, results still the same

My spec:
graphics card: rx 480 (latest driver 18.5.2)
os: windows 10 eterprise (1803)
monitor 1: Iiyama g-master ge2488hs
monitor 2: Samsung EU40EH5300

Please help, sorry for my english