Hello there! Do you have a High-End system, but suffer lag when playing Battlefield 4 Beta?
Well, I am going to teach you how to fix that immediately!
Do as the following :
Open Nvidia Control Panel.
Select manage 3D Settings.
Select BF4 from the drop down box.
Scroll to the bottom and change the vertical sync option to 'adaptive'.
For adaptive vSync to work, make sure you disable in game vSync, and enable adaptive in the nVidia control panel.
You can also try reducing the prerendered frames in nVidia control panel for Battlefield 4.
If that doesn't work. Close down your browser/battlelog after joining a server.