A non-volatile random access memory (NVRAM) is used in a computer system to enhance support to sleep states. The computer system includes a processor, a non-volatile random access memory (NVRAM) that is byte-rewritable and byte-erasable, and power management (PM) module. A dynamic random access memory (DRAM) provides a portion of system address space. The PM module intercepts a request initiated by an operating system for entry into a sleep state, copies data from the DRAM to the NVRAM, maps the portion of the system address space from the DRAM to the NVRAM, and turns off the DRAM when transitioning into the sleep state. Upon occurrence of a wake event, the PM module returns control to the operating system such that the computer system resumes working state operations without the operating system knowing that the portion of the system address space has been mapped to the NVRAM.