My God I'm having a hell of a time to get the M.2_1 to work. I've ruled out bad USB or bad riser components. I'm going to try the "screw & bend" technique after I clean up the M.2 card's contacts. Note that I'm also using DeoxIT chem treatment on the contacts. Otherwise my Asus Z270-P is running seven 1060 SC 3GB's just fine.

I need to vent this out to my mining brothers and sisters: I just got my second rig online yesterday. I had SEVEN (7) bad riser kits. Yes, one entire Mintcell Version 7 (blue cord) bag of six kits was bad and one other kit was bad. I am so pissed. I wasted several HOURS of time trying to figure this out. I'm glad I ordered Version 8 (red cord) and have more coming. If you are stocking up on risers for future rigs, TEST THEM ASAP so you can return them.

After hours of scouring internet anecdotes and my own experience, I am strongly convinced that 75% of the "can't get more than XX GPU's to recognize" is due to junk riser kits. It is amazing how far quality control can go in a factory. I am blown away that they don't even bother testing their crap before shipping it off. A $10,000 test rig at the factory would avoid $100,000's of dollars in RMA expenses.