Virtual topology reconfiguration addresses the issue of overprovisioning in IP-over-WDM optical backbone networks. Contrary to maintaining a static virtual topology, adapting the virtual topology to the dynamic load of the network achieves notable energy savings. Although the goals of energy efficiency and high performance are usually achieved, such schemes suffer from a significant performance degradation, because they overlook the impact of the reconfiguration process. In this work, a novel threshold-based reconfiguration algorithm is introduced, which overcomes the above problem by taking into account the impact of reconfiguration. The proposed RVTM (Reserved Virtual Topology Management) scheme introduces a new threshold system and a new relaxed reconfiguration policy. The new algorithm is focused on reducing the volume of reconfigurations needed to maintain an energy-efficient network, as well as the number of served traffic demands which are affected by the reconfiguration process. Extensive simulation experiments are presented, which demonstrate the benefits obtained by the use of the proposed algorithm, in comparison to the original strict threshold based reconfiguration policy. RVTM yields up to 40% energy savings, while decreasing the number of reconfigurations up to 77%. Additionally, the proposed algorithm reduces significantly the number of rerouted traffic demands and improves the lightpath interconnection.