Wait, by double load do you mean the thickness of the workpiece? Maybe I wasen’t clear, but I didn’t ever try 9mm doc lol. That would be an instant disaster. I see load as the rate at which it is removing material combined with HOW you are doing it. I actually reduced my DOC and speeds a lot. In fact, in one test of my now butchered 3/8 inch plate, I reduced my doc to 2mm and my feed to something like 400mm/m with a .5mm radial cut. I am talking about adaptive clearing, not slots. It sounded better for sure, yeah. But that chatter at 12 and 6 was still there only lighter. So in short, I did go more conservative.
So let me do another test right now. It takes something like 10 minutes. I will be really conservative this time.