Ubuntu 3GB Ram Limitation and Solution

Ubuntu 32-Bit machine is bound to use maximum of 3 GB RAM, Below are the steps to use > 3GB RAM.
$ free -m
Sample output:
             total       used       free     shared    buffers     cached
Mem:          3291        801       2489          0         95        342

-/+ buffers/cache:        363       2927
Swap:         1906          0       1906

Open terminal and type the following command if you are using Ubuntu version Ubuntu v9.04 and earlier:
$ sudo apt-get update
$ sudo sudo apt-get install linux-headers-server linux-image-server linux-server

If you are using Ubuntu v9.10 (Karmic Koala) and above, enter:
$ sudo apt-get install linux-generic-pae linux-headers-generic-pae

Once kernel images installed, just reboot your workstation, type:
$ sudo reboot

After reboot, login into your system and type the following command to verify memory usage:
$ free -m
Sample output:
             total       used       free     shared    buffers     cached
Mem:          8105       1292       6812          0         38        483

-/+ buffers/cache:        770       7334
Swap:         1906          0       1906