This page should answer your questions: http://en.wikipedia.org/wiki/Physical_Address_Extension
You may need to add the /pae boot option to enable this. Assuming you are using XP professional 32bit for the host you will be able to use only 4gb of your total ram for applications (up to 2gb additional ram can be used by the XP Kernel). I haven't tested this myself but this is my interpretation of the information to hand, could be wrong. In XP, by default, the whole system can only access up to 4gb of physical ram. Although an application can see a 4gb flat memory space, 2gb is assigned to the XP kernel and addin cards so an app can only use 2gb of physical memory at any one time, I guess the rest get's swapped out. This can be modified using the /3gb (I think) boot switch which allows your application to address 3gb (with XP kernel and addin cards getting 1GB). Apparently this is usually only a problem for example when using citrix with many users and possibly if you have a video card with >512mb of ram, so you might want to try this. Still, this is all quite confusing and your best bet would be to upgrade to Windows 7 Ultimate or something. See the table in the linked article for a table of allowed physical memory for each operating system. R -----Original Message----- From: vbox-users-boun...@virtualbox.org [mailto:vbox-users-boun...@virtualbox.org] On Behalf Of Klaus Espenlaub Sent: 18 February 2010 13:01 To: pac Cc: vbox-users@virtualbox.org Subject: Re: [vbox-users] Memory over 3Gb pac wrote: > In a XP host with 3Gb of memory if I install 8Gb of memory, XP stay at > 3Gb, but virtualbox (Debian Lenny) can use 5Gb or it's stop by XP > memory ? As usual a question with half the required information missing. You probably mean a 32bit version of XP (there is also XP x64). VirtualBox can only use the memory which the host OS can allocate, so going to 8GB doesn't change anything. Things would be different for the 32bit version of Windows 2003 Server, as it supports PAE which allows the OS to manage up to 64GB. Additionally, on a 32bit host there is a ~1.5-3GB limit per VM, IIRC on Windows it's below 2GB. This isn't affected by PAE. To use more, you need to run a 64bit host OS. Klaus _______________________________________________ vbox-users mailing list vbox-users@virtualbox.org http://vbox.innotek.de/mailman/listinfo/vbox-users _______________________________________________ vbox-users mailing list vbox-users@virtualbox.org http://vbox.innotek.de/mailman/listinfo/vbox-users
