Install the Mac OS driver to improve throughput. (Recommended for Mac OS 10.10)
INSTRUCTIONS & INFO
INSTALL THE DRIVER AND CONNECT: Insert the AT&T Velocity USB Stick into a USB port on your Mac.
Double-click on the AT&T USB Modem icon that appears.
Double-click on the AT&T USB Modem package icon. You may need to enter your password.
Open a web browser, then go to http://attusbmodem or http://192.168.1.1. If Domestic Data is not already enabled, click On then Apply.
UNINSTALL THE DRIVER: Disconnect from the Internet, then remove the AT&T Velocity USB Stick from your Mac.
Open the Applications folder, then double-click on the Uninstall AT&T Velocity USB Stick icon. Note: To open the Applications folder, from Finder, click Go > Applications or press Shift-Command-A.
Click Uninstall. You may need to enter your password. Note: If you have not yet removed the AT&T Velocity USB Stick from your Mac, remove it, then click OK.
You may need to enter your password. When driver removal is finished, click Close. You may need to enter your password.