Appreciation to:
htwaits, fight4yu, alf56-2009 and scirica
htwaits said: There is no reason to use both HDMI outputs unless you have one of the few situations where it's necessary. The main example is the case where you want to do 3d and you have an AVR that can't pass 3d video. Stick with the simple and obvious short of a clear reason to do otherwise.
P.S.; fight4yu has pointed out that another reason for using a second HDMI port would be either an AVR with faulty or unnecessary video processing. A third reason might be owner paranoia.
fight4yu said: In general the less the video chain have to go through the better it is. Your Yamaha AVR might add processing to it that you don't like. I say go experimenting and see.. I did the separate route as my receiver had some 24p bugs in it, and I don't want another receiver to mess with the clean video signal from Oppo.
alf56-2009 said: my Yamaha 665 doesn't play nicely with my oppo 93,I have to run HDMI 1 to my TV and HDMI 2 to the 665 for audio otherwise I get severe handshaking issues.
scirica said: I believe that really depends on the capabilities of your AV receiver. In my case (Anthem MRX-500) Jeff Meier showed me that there was indeed a small amount of video signal loss going through the receiver. Whether this is visible is up for debate, but it was enough for me to run HDMI 1 direct to my Panasonic VT50 and HDMI 2 to the Anthem for audio. Your receiver may do a capable job in which case I wouldn't bother using 2 HDMI cables.
Mike K replys: HT, Fight4, alf and scirica-Thanks.
Whilst acknowledging the paranoia factor, I must also bow to the simple truth that more connections increase opportunity for signal degradation.
Whether the Y-765 has a dirty video "Pass-thru" is not determined at this point. I suspect that the Y-665 is quite different than the Y-765 in digital video (I don't believe that the 665 could up-convert and up-scale to HDMI) and, like the *63 series, has some HDMI issues that haven't shown up on the AVS 765 thread yet.
Having said all that, I have'nt anything else to do with the HDMI # 2 output anyways, and might as well. Paranoria be DAMNED!
Hey, if it might lead to a better visual experience (which we all promise our families and ourselves, eh?) then it must all be worth it. Right?

Mike K