Q: I'm using 4 GB system memory under Windows® XP Professional x64 Edition. Why can't I enable hibernation in the Power Option of Control Panel? It does not have hibernation tab in it!(11/5/2007) A: Windows® XP Professional x64 Edition does not support hibernation with more than 4GB system memory. Please refer to the Microsoft® Knowledge Base for details: http://support.microsoft.com/kb/888575