Hmmmm. That is interesting. I ride with Bear5001 and he has been on a Proto with Cartels for over a year and hauls ass (50 MPH range) and digs deep trenches carving with no chatter issues. I myself find it very quiet at speed.
I do agree on the 390/390 boss. A perfect flex binding for the Proto.
I read so many reviews about how well it held up at speed, which is why I bought it. But I just don't agree, I tried everything including moving my weight more forward, backwards, squat more, stand more etc, etc,. The only thing that really helped was detuning the tip and tale which I found to have too much bite causing extra chatter. Even though it helped a little it's still sketchy at high speeds unless your on perfectly smooth groomers. Any type of bump gets magnified on this board and I find myself popping off of small little bumps that I should be crushing through. I don't know how fast I go because I was never clocked and I don't really trust those GPS tracking apps for speed accuracy but my app says I ride around the 55-60 mph range. I have gone a lot faster on my premier, but the proto is not a free riding stick. But for me it's not really all mountain either. Although I will say its really fun in fresh pow. Again just not too fast.
Man, the Internet sounds like a tuff place to ride.