Use more than 4GB of memory with Ubuntu Linux 32-Bit
Do you have 8G of RAM installed in your system, but the 32-Bit version of Ubuntu Linux is only picking-up 4GB? Here is how to get Ubuntu to recognize more than 4G of memory.
You need to install a kernel that supports Physical Address Extension (PAE). PAE is a feature of x86 and x86-64 processors that enables the use of more than 4 Gigabytes (64GB in total) of physical memory in 32-Bit systems. Here's how to utilize more than 4GB of memory in your Ubutnu 32-Bit Linux system.
For sake of witnessing the change, check your system memory before installing the new Kernel.
The output should be similar to this:
total used free shared buffers cached Mem: 3804 82 3722 0 3 40 -/+ buffers/cache: 37 3766 Swap: 478 0 478
Install the PAE supported kernel packages.
sudo apt-get update
sudo sudo apt-get install linux-headers-server linux-image-server linux-server
Reboot the system and take a look again using the free command. You should see your total memory is now being utilized.
Alternatively you may choose to install the 64-Bit version of Ubuntu which does not require these updates. A 64-bit environment has a theoretical memory address space in the order of 16 Exabytes or 17.2 billion Gigabytes.