Sorry for newbie question, but what’s going on with this feature? If you render some selected piece in track - you’ill have it in the new instrument with lovering RMS ~1.5 - 1 db… Why it is working so? After that i should use maximazer on that sample => again CPU usage 
IN the previous renoise 2.0 release candidates you got what you rendered …altough in some cases the rendered selection was too loud , distorted and clipped …So taktik decided to leave it like it was before ( which is good )
You don’t need to ad a maximizer , just normalize your sample in the editor and adjust your channel volume faders if needed .