I see a lot of people thinking they need external amplifiers. Before spending money, ask yourself, do I actually lack power in my system? And make sure your amp is not the weakest link.
Actually, I find that the internal power amps on most AVRs ARE THEIR weakest links
Except for ICEpowered Pioneer AVRs, most AVRs use a regular AB architecture. That design is ultimately limited by the size of the transformer used in the AVR and for the most part, they are undersized. When you use an external amp like an Emotiva Class AB, their transformers are significantly larger... so a 5 channel power amp would have almost 5x the transformer size of the a single channel amp. That's why we have tests that show a lot of the new AVRs run out of juice when they have to power all the channels simultaneously.
Also, it's not all about the max power deliverable per se, since that's likely to pierce yr eardrums.. but how well your amp can handle transients which in turn leads to microdynamics/details.
When you even take the LR channels out of the equation and drive them with an external power amp, you give more headroom for the rest of the channels driven by the AVR. I found that even without changing anything else (just power amps to LR), the center channel became crisper and dialogue clearer.
Sorry for the OT.
Back to Yamaha... so no DSX/IIz so 2010? Only HDMI 1.4?