Occured with patch 1.26
Playersize >= 40
Massive Red / yellow chains
Massive rubber-banding
Massive Desyncs
Takes players 2+ seconds to die after being killed, etc.
Serverspecs:
OS: Windows 2012
CPU: E3 1245V2 3,4 GHZ+ (4C/8T)
Ram: 64 GB
HDD: Raid 10 SSD
Connection: 1 GBit/s
Arma3-Server seems to consume the same amount of bandwith