> moving the Mac to a new processor architecture (for the second of three times) Four times kinda — maybe five if you want to count PPC32 and PPC64 separately

> moving the Mac to a new processor architecture (for the second of three times) Four times kinda — maybe five if you want to count PPC32 and PPC64 separately but I usually don't since the Intel transition happened so soon afterward that there is really no PPC64 lineage to speak of. I definitely count 32-bit and 64-bit Intel separately though due to the number of years taken to transition, all of the annoying early-Intel-Mac 32-bit EFI issues, and the need to manually opt in to the 64-bit kernel on many machines. In fact Snow Leopard was the first OS to let you do so! The “no new features” tagline was snappy but it's really not true at all :p https://apple.stackexchange.com/questions/261749/in-which-versions-did-macos-transition-from-32-bit-to-64-bit https://apple.stackexchange.com/questions/261749/in-which-ve... sez — “Mac OS X Snow Leopard and above could only be installed on Macs with Intel processors, and introduced a number of fully 64-bit Cocoa applications (e.g. QuickTime X), and most applications were recreated to use the 64-bit x86-64 architecture (although iTunes was a notable exception to this!) This meant these applications could run in 32-bit mode on machines with 32-bit processors, and in 64-bit mode on machines with 64-bit processors. And yes, the kernel was updated so that it could run in 64-bit mode on some limited hardware, and only by default on Mac Pros, while other newer Macs were capable of running the kernel bit did not do so by default.” Relevant articles: - “Mac OS X v10.6: Macs that use the 64-bit kernel” https://web.archive.org/web/20121024223751/https://support.apple.com/kb/HT3770 https://web.archive.org/web/20121024223751/https://support.a... - “OS X: Starting up with the 32-bit or 64-bit kernel” https://web.archive.org/web/20121024194635/http://support.apple.com/kb/HT3773 https://web.archive.org/web/20121024194635/http://support.ap... - https://macperformanceguide.com/SnowLeopard-64bit.html https://macperformanceguide.com/SnowLeopard-64bit.html