20% of physical memory

C:\WINDOWS\system32>powercfg /a
The following sleep states are available on this system:
Standby (S3)
Hibernate
Hybrid Sleep
Fast Startup

C:\WINDOWS\system32>powercfg /HIBERNATE on

C:\WINDOWS\system32>powercfg /HIBERNATE /type reduced
The hiberfile size has been set to: 2564116480 bytes.