I’ve recently found out about Roy Marchbank, and the sheer depth of his technique consistently amazes me. Though his picking hand is incredibly fast, that has already been explored with the concept of hyperpicking. What interests me is his fretting hand, which at times seems to necessitate that each finger on his left hand is as fast as Marchbank’s picking hand. Take, for example, his G4 solo (tabs of which can be found here: https://www.roymarchbankguitar.com/notation-tablature/). From measure 13 onward, there are two note per string patterns that seem to require the reuse of the same two fingers. Play it at the speed indicated, and one would have to lift up both fingers and replace them repeatedly at a rate of 140 bpm 16th notes (or 9.33 Hz)! There are people on this forum who claim they can’t even pick that fast!
I would love if anyone could offer some insight about what Roy may be doing to reach this level of finger speed (if the motion even comes from his fingers at all!)