Apple Wiki
Apple Wiki

Icon of Rosetta 2

Rosetta 2, part of Project Kalamata, is an initiative within Apple Inc. to facilitate the transition of the Mac product line from Intel processors to its own processors through the use of emulation.



Apple WWDC 2005 - The Intel Switch Revealed

Apple had previously announced that it would switch from PowerPC processors to Intel processors in 2005 when IBM's development of the PowerPC G5 could no longer keep up with its product road map.[1] An earlier version of Rosetta was a key component of the transition by allowing PowerPC software to run in emulation on Intel processors.[2]

In April 2008, Apple acquired P.A. Semi for $278 million to bring fabless processor design in-house to the company, and to reduce its dependence on Samsung for central processing units in its mobile products,[3] and later Intel for its desktop products.[4]

Development and announcement

Specifications of the 2020 Developer Transition Kit.

Apple initiated Project Kalamata in 2018 with the goal of developing a 5nm version of the Apple A14 to replace Intel processors by 2021, starting with entry level Macs.[5][6] This was realized in November 2020 with the introduction of new MacBook Air, MacBook Pro, and Mac mini models based on the Apple M1 processor.[7]

Craig Federighi announced Rosetta 2 at 2020 Worldwide Developers Conference on June 22. It allows emulation of Intel processors on systems built with Apple processors, such as the 2020 Developer Transition Kit, which uses an Apple A12Z processor.[8] The performance hit from Rosetta 2 was reportedly around 20%, allowing the newer M1 processor to run Intel software in emulation faster than Apple's Intel-based models.[9] However, some users expressed concern that the swap files being generated by the translation of non-native code were wearing out the life expectancy of the affected models' solid-state drives.[10]


  1. The Apple Developer Transition System – a Trojan Horse PowerMac by Adam Rosen, The Vintage Mac Museum. 2014-05-29.
  2. Rosetta. The most amazing software you'll never see., Apple Computer. Archived 2006-01-13.
  3. "Apple Buys Chip Designer", Forbes. Retrieved on 2008-04-23. 
  4. Former Intel engineer says Skylake problems were turning point for Apple’s ARM Mac transition by Filipe Espósito, 9to5Mac. 2020-06-24.
  5. Apple Project Kalamata – future Mac’s may have custom chips (opinion) by Ray Shaw, GadgetGuy. 2018-06-18.
  6. Apple Aims to Sell Macs With Its Own Chips Starting in 2021 by Mark Gurman, Debby Wu, and Ian King, Bloomberg. 2020-04-23.
  7. Apple unleashes M1, Apple Inc. 2020-11-10.
  8. WWDC Special Event — June 22 by Apple, YouTube. 2020-06-22.
  9. I love that Apple’s M1 can easily shrug off a 20% performance hit just to emulate x86_64 and still be faster than the Intel chips in the rest of Apple’s lineup by Steve Troughton-Smith, Twitter. 2020-11-15.
  10. Swapgate and Rosetta 2 by Yebubbleman, MacRumors Forums. 2021-06-16.

See also

External links


IPod Nano 6.jpg This article is a semistub. You can help by expanding it.