it seems as of late that yamaha receivers are lacking in the power department in general. bench testing seems to be showing their performance in multi-channel surround to be 50% of what they are rated.
I would suggest like I said, get the 867 as it has pre-outs for an external power amp, or look at Onkyo, Integra, Marantz, Denon, NAD, something thats pulling over 6 amps of current. JMO.
good luck in your search.
Dynaudio Focus 260s, Focus 210C, DM 2/6, Hsu VTF3 MK5 HP, Oppo BDP-103, NaimUniti 2, Naim Stageline N, Pro-ject 2xperience Classic, Marantz SR7007, 60" 4K Samsung LED LCD