Maybe this thread be of some help to you:
http://www.avsforum.com/avs-vb/showthread.php?t=671734
The bottom line is don't pay too much attention to power ratings advertised by Yamaha.
http://www.avsforum.com/avs-vb/showthread.php?t=671734
The bottom line is don't pay too much attention to power ratings advertised by Yamaha.