Many of us not clear about the usage of /3GB switch, what it’s all about and why we require a 3GB switch in Boot.ini file
Standard memory configuration of 32bit system is 2Gb, and Windows 2000 & 2003 can use up to 4Gb of memory.
The /3GB switch changes the 4Gb addressable space from the default 2Gb kernel space and 2Gb user mode space to 1Gb kernel space and 3Gb user mode space. Most application services actually run in user mode space and operating system run in kernel mode, this will improve the application performance, application like SQL amd Exchange
What about if you have more then 4GB memory? And
Some of the advanced operating system will support more then 4 GB memory, like Windows 2000 Advanced Server supports 8 GB of physical RAM and Windows 2000 Datacenter Server supports 32 GB of physical RAM
Windows Server 2003, Enterprise Edition supports 32 GB of RAM and Windows Server 2003, Datacenter Edition supports 64 GB of RAM
We have to use /PAE switch in the Boot.ini file, to address more than 4 GB of physical memory, I will be explaining this in my upcoming article