Not all 2Pac were built the same. Same voltage, but one throws many HW errors, another does a few HW errors, and the last one throws 0 HW errors. This is why I asked if I could run each device with their own frequency (Mhz). Rather than device number, the serial number seems like a better unique identifier and maybe use the GSx hardware model if necessary. Maybe something for cgminer-gekko 4.11