I also tried several launch settings, such as -maxMem=6144 -cpuCount=6, ect, doesn't help. My machine config is, CPU Intel Q9550, MSI gtx 770 lighting, 8G memory, Windows 7 64bit. I have tried Nvidia driver 320.18 and 320.49beta, it doesn't matter.
I remember when it was Arma 3 alpha, I never had this problem.

Today I reinstalled the Arma 3 beta and Nvidia display driver. It seems the situation getting worse, now on every server I can't last for 10 minutes. From several seconds to several minutes, I will get the "no message" error, and disconnected after 90 seconds. During the 90 seconds, nobody can hear my voice. The multiplayer is totally unplayable.
Can you tell me what information do you need to pin point the defect? I'd be glad to provide.

This start to happen in Arma 3 beta under Window 7 64bit