Echoing Bernard, I have an Onkyo TX-DS797 (older version of the 703) driving two 8 ohm fronts, two 6 ohm surrounds, and a 4 ohm center channel. I've never had a problem. I don't listen at earsplitting volume, but I get it plenty loud enough for me.

Jack

"People generally quarrel because they cannot argue." - G. K. Chesterton