Editing Microprocessor (section)

===64-bit designs in personal computers===
While [[64-bit]] microprocessor designs have been in use in several markets since the early 1990s (including the [[Nintendo 64]] [[gaming console]] in 1996), the early 2000s saw the introduction of 64-bit microprocessors targeted at the PC market.

With AMD's introduction of a 64-bit architecture backwards-compatible with x86, [[x86-64]] (also called '''AMD64'''), in September 2003, followed by Intel's near fully compatible 64-bit extensions (first called IA-32e or EM64T, later renamed '''Intel 64'''), the 64-bit desktop era began. Both versions can run 32-bit legacy applications without any performance penalty as well as new 64-bit software. With operating systems [[Windows XP x64]], [[Windows Vista]] x64, [[Windows 7]] x64, [[Linux]], [[BSD]], and [[macOS]] that run 64-bit natively, the software is also geared to fully utilize the capabilities of such processors. The move to 64&nbsp;bits is more than just an increase in register size from the IA-32 as it also doubles the number of general-purpose registers.

The move to 64&nbsp;bits by [[PowerPC]] had been intended since the architecture's design in the early 90s and was not a major cause of incompatibility. Existing integer registers are extended as are all related data pathways, but, as was the case with IA-32, both floating-point and vector units had been operating at or above 64&nbsp;bits for several years. Unlike what happened when IA-32 was extended to x86-64, no new general purpose registers were added in 64-bit PowerPC, so any performance gained when using the 64-bit mode for applications making no use of the larger address space is minimal.{{citation needed|date=June 2013}}

In 2011, ARM introduced the new 64-bit ARM architecture.