Physical Address Extension

In computing, Physical Address Extension (PAE) is a processor feature to enable 32-bit IA-32 central processing units (CPUs) to access physical address space larger than 4 gigabytes by extending the paging schema .^[1] It allows up to 64 gigabytes of system memory to be addressed by a 32-bit processor.^[2]

PAE was first introduced with the Intel 32-bit processor Pentium Pro.^[2] Since then it has been a feature on all Intel processors except some Pentium M mobile processors.^[2] Athlon or K7 is the first processor from AMD supported PAE. Now all AMD processors support PAE.^[2] In addition to processor support, PAE requires the operating system (OS) to support it.^[3] Windows 2000 was the first OS to support PAE.^[3]

Desktop Processors

Processors	Physical Addressing Bit Width
Intel Pentium Pro/Pentium II/Pentium III/Pentium II Celeron/Celeron	36 bits
Intel Pentium 4/Pentium 4 Celeron/Pentium D/Celeron D	36 bits
Intel Core 2/Pentium Dual-Core/Celeron	36 bits
Intel Core i3/i5/i7/Celeron/Pentium	36/39 bits
AMD Athlon 64/Athlon X2/Sempron/Sempron X2	40 bits
AMD Athlon/Athlon II/Sempron/Sempron X2	48 bits
AMD C-50	36 bits
AMD APU A4/A5/A6/A8/Athlon/Sempron	48 bits