Hi Alan.
Unfortunately, I changed PC recently and did not transfer "My Favorites" which contained an article about something new they are doing with the 805/875 (only for the main channels) to better support 4ohms. Since I have read that 3-4 months ago, I don't even recall how I came accross it, but I am pretty sure it was coming (the article or a link to the article) from an answer from Onkyo itself. I checked quickly and did not find anything on their USA site (could have been the Asia one).
I do not necessarily disagree with not recommending the Onkyo for people with M80 who needs (can afford) one piece of equipment to do everything. I picked this receiver because it was more powerful than what I currently need, while having the right feature set as pre/pro for my future needs. I was thinking (when I move or the time comes in a year or two) going "separates", maybe even with the little 8-channel devil now offered by Axiom. So whatever problems there could be, it is highly unlikely I will hit them (I might have had with a 65W Onkyo receiver though).
As for testing, I just played a cello suite by Bach, Roussel's 3rd symphony and the scherzo from Beethoven's 9th at higher volume (+6 db on the receiver). It was WAY louder than what I like, but it was quite bearable and did not feel strained at all. After 40 minutes (most of it just with the M80s at +9db to "make it worse"), the receiver was not even warm. I know this is highly inconclusive, but it seems that for my current "current" needs, I should not experience any problems.
Again, the most important thing is to understand your needs, your budget and your plans for the future. As an example, M60s would have been quite sufficient for now for me, but I don't want to change speakers again in 1-2 years when I move to a neighboor-less environment! So I went with M80 (and boy am I happy). When I need the power, I will get the power. But, again, each situation is different. To make it worse, knowing that a problem may exist has a tendency to make it happen!
If I have a sudden revelation about that article (I remember that there was a picture of the inside of the receiver) I will post it.
Time to go back to some music now!
