diytube.com

The powerful 7-channel amplifier section features identical power amp design on all channels along with high current discrete power output devices. Rated at 105 watts per channel (8 ohms, 20 Hz~20 kHz, .08% THD), the AVR-X3100W is also rated to drive lower impedance speakers, down to 4 ohms. Our new Eco amplifier mode automatically adjusts power output based on volume level, and an on-screen Eco meter lets you see the power consumption savings in real time.

Isn't that the one and only function of the volume control?

This is from Newegg.

Problem with all 7-channel amps, regardless of name on the front is they're like a Volvo - take 'em off the lot and they've lost 90% of their resale value