How can I find out that my CPU supports 64bit operating systems under Linux, e.g.: Ubuntu, Fedora?
Find 'lm' flag. If it's present, it means your CPU is 64bit and it supports 64bit OS. 'lm' stands for long mode.
Note the spaces in
Update: You can use the following in terminal too:
This works on Ubuntu, not sure if you need to install additional packages for Fedora.
If your CPU is a 64bit one (x86-64), you can use it with a 64 bit OS.
Here is a list of 64bit CPUs: http://en.wikipedia.org/wiki/64-bit#Current_64-bit_microprocessor_architectures