The DOS will always take a percentage of the physical RAM on the motherboard leaving the rest for the User. By default the Windows Operating System will use 50% of the physical RAM installed on the motherboard leaving the user the remaining 50% this can be changed using a switch in the boot.ini file
was originally meant to be used in systems that have 3GB or more of RAM something that is no longer quite as rare as it used to be Windows XP SP3 will support upto 4GB although on a 32bit (x86) version of Windows will acually see 3.25gb that is the limitation.
However, even if you don't have 3 GB or more of memory, you can still use the /3GB
switch. the switch can have any value between 2048 (2 GB) and 3072 (3 GB) megabytes. It needs to be expressed in decimal notation.
The /3GB switch applies to 32-bit
systems only (x86).
Example with Windows XP SP3 Home Edition with the recovery console installed this gives you the option of default 50-50% split or the 3GB switch 75-25% split.
parameter enables, disables, and configures Data Execution Prevention (DEP)
, a set of hardware and software technologies designed to prevent harmful code from running in protected memory locations using the optin
switch enables DEP only for operating system components, including the Windows kernel and drivers. Administrators can enable DEP on selected executable files by using the Application Compatibility Toolkit (ACT).
parameter specifies the amount of memory, in megabytes, that Windows cannot use in this example, /burnmemory=128
will reduce the physical RAM memory that is available to Windows by 128 MB.[boot loader]
multi(0)disk(0)rdisk(0)partition(1)WINDOWS="Microsoft Windows XP Home Edition 3GB Switch" /noexecute=optin /3GB /fastdetect
multi(0)disk(0)rdisk(0)partition(1)WINDOWS="Microsoft Windows XP Home Edition " /noexecute=optin /burnmemory=128 /fastdetect
C:CMDCONSBOOTSECT.DAT="Microsoft Windows Recovery Console" /cmdcons
Check out the noexecute and the 3GB switch plus all available boot.ini switches HERE
I suggest that you use AnalogX MaxMem
it is a realtime physical memory management program that
automatically ensures that you always have as much physical memory
available as possible used with the 3GB switch you should never have memory issues ever again.