DRAM, or Dynamic Random-Access Memory, is the type of memory that is erased when a Cisco device is rebooted. DRAM is used to store the running configuration and routing tables of the device. Since DRAM is volatile memory, its contents are lost when the device is powered down or restarted. This is in contrast to non-volatile memory types like flash and NVRAM, which retain their contents even after a reboot1. Reference := Types of memory on a Cisco device - Study-CCNA