Zac, it has more to do with the internal bec of your esc and power hungry servos than it does with what battery you're running. Some receivers will operate at a lower voltage, created from the load of a power hungry servo like the Savox. Others (receivers) won't, like the DSM1 receivers listed by the OP.
I run DSM2 receivers with Savox (they were free) servos and have no issues. Running Orion Pro v10 esc's, fyi.