An in-depth characterization of the thermal reset transition in RRAM has been performed based on coupling self-consistent simulations to experimental results. A complete self-consistent simulator accounting for the electrical and thermal descriptions of the conductive filaments (CFs) has been developed for the numerical study of the temporal evolution of the reset transition in RRAM. The CFs series resistance, including the contributions of the setup and Maxwell components, has been included in the calculations. Using this simulation tool, we have been able to reproduce many experimental details of the experimental reset data obtained in Cu/HfO2/Pt devices. In doing so, we explained the current steps observed in some reset cycles by considering CFs with several coupled branches that break down at different times. The reset voltage dependence on the initial resistance of the CF has been analyzed and the relevant role played by the CF shape has also been demonstrated. In this respect, devices with a same initial resistance but different CF shape can switch at different voltages. A simulation study of the reset voltage distribution obtained for these devices has also been performed in order to explain the variability of the experimental samples. © 2013 AIP Publishing LLC.