Those batch1 or something else?
It is possible to overclock any batch.
Do tell. What hardware modifications made?
I've no problem pulling these outta the factory chassis and modding...
yes I know, my question was about the hardware change and not how to set 900 on frequency.

On the right is the original hash panel. Left - changed.
The bottom line is that the chips should get extra power.
Detailed step-by-step instructions from me will not be, as long as I make money on these changes. Excuse me. My message was for those professionals who work with electronics. These people know that this is possible and how.
I see -- thank you. Did you make any cooling changes? That is my current limitation of knowledge -- thermodynamics is more of a challenge than the electronics aspect. I'm trying to simultaneously optimize cooling on basically 24 Z9 minis.