Any x86_64, or ia64 CPU is supported for running para-virtualized guests. To run i386 guests requires a CPU with the PAE extension. Many older laptops (particularly those based on Pentium Mobile / Centrino) do not have PAE support. To determine if a CPU has PAE support, run the following command:
The above output shows a CPU that does have PAE support. If the command returns nothing, then the CPU does not have PAE support.