I did a little more research and found this:
http://www.onkyousa.com/model.cfm?m=...class=Receiver
Here's an excerpt:
Amplifier Section
Power Output
Front L/R
90 W + 90 W (8 ohms, 20 Hz–20 kHz,
0.08%, 2 channels driven, FTC)
105 W + 105 W (8 ohms, 1 kHz, 0.7%,
2 channels driven, FTC)
110 W + 110 W (6 ohms, 1 kHz, 0.1%,
2 channels driven, FTC)
also saw this:
http://www.gspr.com/onkyo/images/txsr605_rear_300.jpg
says on the back:
"CAUTION: SPEAKER IMPEDANCE 6ohms - 16 ohms"
Does this mean that the output is adjustable? (any 605 owners out there confirm?)