FYI: with those 2x Z9 from batch2, i§m not able to go over 600MHz, when i overclock more, they runs just about 1.5 KSol.,.. Asic status is oooo for al boards
Doesnt matter if i set 610, 630, 650 or more, looks the same

Something as:
Chain#   ASIC#   Frequency   KSol/S(RT)   HW   Temp(PCB)   Temp(Chip)   ASIC status
1   4   666   1.62   0   33   41   oooo
2   4   666   1.27   0   33   41   oooo
3   4   666   1.39   0   35   44   oooo

Compared to 600 MHz:
Chain#   ASIC#   Frequency   KSol/S(RT)   HW   Temp(PCB)   Temp(Chip)   ASIC status
1   4   600   4.30   0   50   64   oooo
2   4   600   4.09   0   46   60   oooo
3   4   600   4.62   0   49   61   oooo