Recently one of my friend bought 2 GB RAM for his PC. He already had 2GB installed and he added more 2GB to his desktop computer.But his XP showed only 2 GB RAM. This is very common problem.By default Windows XP supports only 2GB of RAM on 32-bit systems.It is fact that 64-bit systems can support 4 GB of RAM .But very few people know that even 32-bit systems can support up to 4GB of RAM.This can be done by enabling the PAE(Physical Address Extension) on your PC.Now a days almost all processors support PAE.
How to enable PAE on XP:
To enable PAE in Windows XP you have to edit the boot.ini file. Open boot.ini file. It will be there in your system drive. Suppose your OS is installed in C drive then go to run and type c:\boot.ini and hit enter.Add “/ PAE” at the end of the file.
It would look something like this:
multi (0) disk (0) rdisk (1) partition (1) \ WINDOWS = “Microsoft Windows XP Professional” / noexecute = OptIn / fastdetect / PAE
Don’t change anything else in boot.ini or your PC will not boot.Just add / PAE at the end of the line.
Now restart your PC and check if your computer is showing 4 GB RAM. To do this right click on My computer and select properties.Click on general tab and see if it is showing 4GB or not. If it shows then it means that you have done everything correctly and you can use complete 4Gb of your RAM.
Enable PAE under Vista:
It is very easy to enable PAE under Vista. Open cmd and type
BCDEdit / set PAE forceenable
Now it should show 4GB of RAM in Vista.
Warning:Use PAE only if you really have 4GB of RAM or your PC may not work properly. Or if you have got some extra money I will recommend you to go for 64-bit system.
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