If the recorded AVI file doesn't have the audio and video synchronized, it can be the codec or media player's problem.
Try VLC media player. VLC media player can minimize the audio and video sync problem.
- VLC Media Player:
http://www.videolan.org/vlc/
If you still have the lag with VLC, try the "Low-end PC" preset of Bandicam
For more information, visit
http://www.bandicam.com/faqs/how_to_red ... recording/