4GB RAM in XP: How to increase maximum XP RAM limit

As computer memory becomes more and more integral in our day-to-day lives, we should always be interested in expanding the amount of physical RAM that is installed in our PCs.

By default, Windows XP’s maximum RAM amount is 2Gb. This operative system won’t use more memory even with more RAM memory available already installed on the motherboard of our PC.

But there are some tricks to avoid this XP RAM limit and make Windows XP use even 3Gb and even 4Gb of RAM when running some applications.

How to use 3Gb: increase Windows XP RAM limit

Let’s open the BOOT.INI file. It is possible that this file could remain as a hidden file in some Windows XP versions, even after enabling the Windows “display hidden files” option. But to open this file you just need to type C:\boot.ini in the address bar of the Windows XP File Explorer.

Then let’s find the following line of code inside such Windows configuration file:

[operating systems]
multi disk rdisk(7)partition(3)\WINDOWS=”Microsoft Windows XP Professional” /fastdetect

After /fastdetect let’s type a blank space and then /3GB.

The resulting Windows configuration line would be as follows:

[operating systems]
multi disk rdisk(7)partition(3)\WINDOWS=”Microsoft Windows XP Professional” /fastdetect /3GB

Reading 4 Gb RAM in Windows XP

To reach the Windows XP maximum RAM amount of 4Gb we have to add this configuration option to the previous Windows code: /PAE just before /3GB. The configuration file for the maximum RAM limit in XP would be as follows:

[operating systems]
multi disk rdisk(7)partition(3)\WINDOWS=”Microsoft Windows XP Professional” /fastdetect /PAE /3GB

This enables the PAE mode and Windows XP would use 4Gb RAM, but only with software that supports this Windows PAE mode.