So i figured out that me, some friends and some reddit users have pretty bad FPS in some areas around Electro.
This did NOT HAPPEN in the first 0.63 Patch a few months ago.
Topic on reddit about it: https://www.reddit.com/r/dayz/comments/aqtmn5/anyone_else_got_only_around_45fps_around_electro/

First my specs:
GTX 1080
i7 4790k
16GB RAM
DayZ on SSD

I most of the time got 80-100 FPS in dayZ.
BUT in parts of Electro and Cherno, especially near Policebase, Firestation, Towncenter my FPS drops down t 40-45.
This happens also to some friends.
The first version(s) of 0.63 this did not happen, we had constant very high fps everywhere.

As it seems that this is not happening to everyone my guess:

• It is related to some special hardware setups (not meant as to bad or old hardware)
• Maybe when a lot of items are lying around in the area of a few hundret meters
• Maybe if a lot of People are in the network bubble
• Maybe also its about some special buildings
• Maybe if a lot of stashes, barrels, tents are nearby.