Different network different signal strength
I ever bought 2 prepaid cards from ST and SH just to try, omitted M1 because it sucks no matter where you are
Picked whichever has a better signal strength (lower dBm the reading, the better it is, battery drain is slower on your HP)
Goto your HP ,settings > about phone > status > SIM status > network > SIM status 1 or 2
The lower the dBm reading, the better
Example like eight network, 90+dBm, means not as good
Anyway, M1 has at least 90+dBm to 100+dBm, that's why the battery drain on HP