
Hello Steve,
The organ settings polyphony will always override the General settings polyphony management unless you have a value of 0 in the Organ settings in which case the General settings would then take effect.
I would say one of two things are happening, either your polyphony is set too high in which case just try lowering it until the popping is gone. Or you have audio overload (clipping) in which case you can simply turn down the audio output levels until the popping is gone.
77% load on the processor *should* be OK but depending on your OS settings this may be a little too high. Lowering the polyphony settings should lower this value. I would say that 4500 is probably too high for the i7, if you run the polyphony testing organ you should be able to try and determine that most acceptable polyphony for your computer.
However my guess would be that your audio output just needs to be turned down and that you are experiencing audio distortion. You should be able to view the RME control panel meters which should be in (or near) the red if clipping is occurring.
I hope that helps.