Atomic migration and electronic switching of bi-stable centers in conducting filaments formed in nanooxide based resistive random access memory (RRAM) cells are modeled and analyzed as competitive mechanisms determining their operation frequency. They are mediated by the filament growth dynamics. Atomic migration is responsible for a slow change of the filament resistivity with typical switching times in the millisecond range. Fast switching with the shortest nanosecond delay can be achieved using bi-stable electronic centers in the filaments. Possible configurations of such centers are discussed.