A memory system that has a multi-channel volatile memory subsystem is coupled to a non-volatile memory subsystem to provide independent, configurable backup of data. The volatile memory subsystem has one or more main memory modules that use a form of volatile memory such as DRAM memory, for which the NV subsystem provides selective persistent backup. The main memory modules are dual in-line memory modules or DIMMs using DDR SDRAM memory devices. The non-volatile memory subsystem (NV backup) includes an NV controller and non-volatile memory NVM. The NV backup can also include a memory cache to aid with handling and storage of data. In certain embodiments, the NV controller and the nonvolatile memory are coupled to the one or more DIMM channels of the main memory via associated signal lines. Such signal lines can be, for example, traces on a motherboard, and may include one or more signal buses for conveying data, address, and/or control signals. The NV controller and the non-volatile memory can be mounted on the motherboard.