I'd like to see if anyone else can confirm this, but when opening duplicate stops, the cpu staying with 1% of the value of the single stop performance--including with couplers applied, and I can use full organ (the tutti piston) and all default couplers without audio breaking up, where I couldn't do that before.  (It hovers at 63% of cpu on my system at 96 polyphony and 512 latency on a three-voice fugue, which is substantially improved stability and performance for full organ.)  It also doesn't sound like the sound is getting amplified/over-dubbed either (though I haven't confirmed with an SPL meter), which is great!