You guys, what we just learned means the Intel transition wasn't some 2005 pivot; it was literally baking in since June of 2000! An engineer named JK Scheinberg built a x86 version of Mac OS X as a personal side project so he could work from home — his boss called it "Marklar." The only reason this hobbyist build became critical is that Apple's PowerPC G5 chips were, in the words of both Steve Jobs and Tim Cook, basically unusable. They ran too hot to ever fit into laptops — the G5 was the 64-bit chip they needed but could never package without melting it, which forced them back onto downgraded versions of the older G4 silicon for their MacBooks and iBooks. So "Marklar" wasn't just some pet project; it was a hidden contingency plan that had been quietly growing while Jobs privately trashed Motorola chips behind closed doors since 1997.
Then came June 2005 when Jobs publicly unveiled OS X 10.4 running on Intel and let slip the existence of Marklar by mentioning all versions were now compiled for both architectures "just in case." The actual transition involved a Developer Transition Kit available after WWDC 2005 — $999 per unit plus your dev account, which developers had to return by late 2006 in exchange for a real retail Mac. They even included Boot Camp so Macs could run Windows natively via disk partitioning and dedicated drivers with an app to switch back to macOS on reboot, while Rosetta handled the legacy PowerPC apps under a compatibility layer — the exact same strategy Apple would repeat during the Apple Silicon migration years later! That design continuity extended all the way down to hardware; the first Intel iMacs and MacBook Pros were intentionally styled after their PowerPC predecessors so users wouldn't feel unsettled.
Source: https://arstechnica.com/gadgets/2026/06/20-years-of-intel-macs-why-apple-switched-and-why-it-switched-again/
Then came June 2005 when Jobs publicly unveiled OS X 10.4 running on Intel and let slip the existence of Marklar by mentioning all versions were now compiled for both architectures "just in case." The actual transition involved a Developer Transition Kit available after WWDC 2005 — $999 per unit plus your dev account, which developers had to return by late 2006 in exchange for a real retail Mac. They even included Boot Camp so Macs could run Windows natively via disk partitioning and dedicated drivers with an app to switch back to macOS on reboot, while Rosetta handled the legacy PowerPC apps under a compatibility layer — the exact same strategy Apple would repeat during the Apple Silicon migration years later! That design continuity extended all the way down to hardware; the first Intel iMacs and MacBook Pros were intentionally styled after their PowerPC predecessors so users wouldn't feel unsettled.
Source: https://arstechnica.com/gadgets/2026/06/20-years-of-intel-macs-why-apple-switched-and-why-it-switched-again/