free -mFor reference, I know that my PC has 4GB of physical memory installed and the result of the command above shows:
total used free shared buffers cached Mem: 4012 1837 2175 0 451 722 -/+ buffers/cache: 662 3349 Swap: 9538 0 9538If you have more than 3GB of physical memory installed and if you haven't specifically enabled PAE for your ubuntu desktop installation then I'm betting that the total Mem you'll be seeing is LESS than the actual physical memory installed in your machine. To fix this, you simply have to install a PAE enabled kernel. Run the following commands in a terminal:
sudo apt-get update sudo apt-get install linux-server linux-headers-server linux-image-serverReboot your system. To check if you have the correct kernel running and all your mem enabled:
uname -a free -mYou should see an ubuntu server kernel running and the correct amount of memory is available for use. Did it work for you? You are welcome to post your comments/questions or better yet, link to this post, blog about it and tell all your friends who might find this post useful.