Thinking of upgrading your 32 bit Linux machine beyond 4GB of memory? Consider the following:
Does your CPU support Physical Address Extension to address beyond 4GB? Here is how to check:
If you see “pae” flag returned install a PAE kernel and reboot. On CentOS 5.x as root:
Do you have a single process that may need to address more than 4 GB of RAM? If so, you need to use a 64bit kernel. Check to see if your cpu supports 64bit instructions.
if you see “lm” flag then your cpu supports 64bit instructions, it is possible to upgrade your current distro to 64bits which is normally not supported by most distro’s or reinstall the entire thing from scratch.