well, i tried that bmminer880 on ~20 S9 13.5T and 14T models, so 15 are good, but 5 rest(only 13.5T) show Chip temp above 100C with even 650 freq in 1-2min after start. i dont understand what is the difference between that antminers, all have identical spec: S9_V2.54 HW: 16.8.1.3 Bmver: 2.0.0   Firmware: Fri Nov 17 17:37:49 CST 2017

any thoughts?