However, for users who has UPS, or using laptop or notebook computer which has batteries to fall back on power outage, Hybrid Sleep is not necessary, as most system with backup power is configured to shutdown automatically or goes into hibernation when the battery charge level falls below certain critical level. The trade back is that to let computer goes into sleep takes a while longer, as system will save the state of operating system environment into memory as well as hibernation file (hiberfil.sys) as in the process of hibernating so that unsaved data won’t disappeared if power is cut. Hybrid Sleep feature in Windows provides a safeguard for computer system such as desktop PCs and workstations, which does not have backup power supply such as battery, from losing running programs and open files when encountering power blackout while in sleep state.
