Are you just talking about stereo, or are you running a full 5 speaker or 7 speaker setup?
If it's just stereo, the Onkyo 805 should certainly be fine. If it's 5 or 7 speakers though, you might have a few issues at higher output levels or during loud peaks.
You could also bi-amp using the option on the Onkyo 805 to use the 6th and 7th channels if it's just the front L/R speakers.