
In computing, Physical Address Extension (PAE), sometimes referred to as Page Address Extension, is a memory management feature for the IA-32 architecture. PAE was first introduced in the Pentium Pro. It defines a page table hierarchy of three levels, with table entries of 64 bits each instead of 32, allowing these CPUs to access a physical address space larger than 4 gigabytes (232 bytes).
The page table structure used by x86-64 CPUs when operating in 64-bit mode further extends the page table hierarchy to four levels, extending the virtual address space, and uses additional physical address bits...