The main difference between InternalSuspend Suspend is that
InternalSuspend does not clear the current history state.
Must be extra cautious not to damage the history integrity while in InternalSuspend mode.
Requirements
Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2