> Among Intel's expressed benefits for a 64-bit mode-only architecture is removing ring 1 and 2, dropping 16-bit addressing support, eliminating ring 3 I/O port accesses and the string port I/O, simplified segmentation model, and removing some unused operating system bits.
> Under this proposal, those wanting to run legacy 32-bit operating systems would have to rely on virtualization. To further clarify, 32-bit x86 user-space software would continue to work on modern 64-bit operating systems with X86-S.