FWIW, I have been using PL4 on a new M1 MacBook Air, 8 CPU/8 GPU, 8 GB RAM with Adobe Bridge and Affinity Photo both at the same time and occasionally adding in Topaz Studio for some special stuff and have seen no RAM related issues (unresponsive, BBOD, long processing times, etc.). I have been working with Nikon D7500 RAWs. I will say, I do not use PL4 at all for management (Bridge serves all those needs).