Once I knew that booted, there’s a bloody excellent chance 6600 will work on much lower Vsoc
So back to bios, set 6600 C28 1.48VDD and began minis testing, TM5 Usmus profile is notorious for picking up Vsoc (or lack of) and Linpack & Ycruncher will follow after TM5 finishes its 4 hour cycle
Also purchased Grizzly CPU frame 🙏