I have the same setup as you and have similar results. One thing to consider I thought was it is loading almost 3.8gb studio grand piano in as well. That is a lot bigger than my EZkeys default sample. It also takes a while in the Stand Alone Program as well so I am sure it has nothing to do with S1Pro 6.5.


BIAB 2025 Ultrapack- Studio One Pro 7 Windows 11, Mac Mini M4 with Logic Pro 11, Melodyne Studio