With a simply modified circuit design connecting a Pt/NiO/Pt capacitor to a serial load resistor $(R_{L})$, resistive switching (RS) characteristics are significantly improved. Distributions of current at low-resistance state and switching voltages during reset and set processes are much reduced, and RS endurance is much enhanced. Using percolation theory, we find that a multiply connected conducting filament (CF) is preferentially formed in a Pt/NiO/Pt capacitor serially connected to an $R_{L}$ of 1 $\hbox{k}Ω$ . The multiply connected CF may provide uniform heat distribution to a Pt/NiO/Pt capacitor, resulting in reduced randomness during heat-assisted reset process and improved RS characteristics.