FaceTime for Mac: Troubleshooting FaceTime
Particularly if you have not restarted your entire system for a long time, restarting your entire communications link may also help. Shut down everything and then restart your modem, router, wireless access point (if it is a separate device), and computer in order. Let every device complete its power-on self-test before restarting the next device.
You can also check the actual speed available to you by using Speedtest.net. Do not have any other internet connected apps (like email, etc.) open while you do the test. If your Speedtest shows speeds much lower than you expect, someone may be pirating bandwidth from your wi-fi, or, perhaps, other people sharing your network are using computers or connected games while you try to FaceTime.
Message was edited by: EZ Jim
Mac OSX 10.8.4