Install More Than 4Gb Memory in 32 bit Ubuntu - How to Install PAE ( Physical Address Extension)

If You Install More than 4 GB Memory in your 32bit ubuntu Machine It will not access the memory beyond 4GB.The x86 architecture presently uses only 36 bits out of 52 bits possible. On x86-64 processors, PAE is obligatory in native long mode; currently 40 bits are used out of 52 bits possible. How do I find out if my Linux kernel supports 36-bit or more physical addressing?

$ sudo grep physical /proc/cpuinfo

shows

physical id : 0
address sizes : 36 bits physical, 48 bits virtual .........


$ free -m will show only <>$ sudo apt-get update
$ sudo sudo apt-get install linux-headers-server linux-image-server linux-server
Once kernel images installed, just reboot your machine ,

$ sudo reboot
After reboot, login into your system and type the following command to verify memory usage:
$ free -m