Same issue here. I have a strong connection and use my pc also for work. Can go for 12 hours straight with no problems. Can play any kind of game, single or multiplayer smoothly. Sometimes, when i start Dayz, i enter the first server but the screen keeps being black before spawning and when i get out no more refresh. I quit the the game and connection is lost, wiped out. I need to restart the pc to have it up again. Since i'm from Italy i doubt this is provider related. Some local pc programs and applications can be discarded too. It must be something we all have in common, like some popular program as an antivirus or similar. Maybe if we post what we have intalled we can figure it out.