What Is Intel® Extended Memory 64 Technology?


Product Information & Documentation



Intel® Extended Memory 64 Technology (Intel® EM64T) is a technology that enhances server and workstation platforms with 64-bit addressability and related instructions. Since the last quarter of year 2006, all mobile, desktop, and server processors based on the Intel® Core™ Microarchitecture have supported the Intel® EM64T.

The table below lists 32-bit operating system, applications, and drivers and map it to its corresponding 64-bit mode.

Legacy Mode Compatibility Mode 64-bit Mode
32-bit operating system 64-bit operating system 64-bit operating system
32-bit applications 32-bit applications 64-bit applications
32-bit drivers 64-bit drivers 64-bit drivers
  4 GB address space 64-bit flat virtual address space
  GPRs are 32-bit GPRs are 64-bit