realsched.exe is a program which schedules for manual update checks for Real Networks products.
This is a non-essential process. Disabling or enabling this is down to user preference however disabling may prevent notification of updates.
Non-system processes like realsched.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that your registry has suffered fragmentation and accumulated invalid entries which can affect your PC's performance. It is recommended that you
check your registry to identify slowdown issues.