The Macintosh community celebrated a significant milestone as a user demonstrated a Quadra 650 booting with a Motorola 68060 CPU for the first time. This development marks a notable shift in the ongoing rivalry between Macintosh and Amiga, as fans of the latter once claimed superiority due to their use of advanced 68k processors. The achievement was shared by a user known as [zigzagjoe] on the 68KMLA forum, highlighting the enduring innovation within the retro computing community.
Historically, the fastest machines running Macintosh software were often Amiga or Atari systems, which leveraged 68060 accelerator cards. The Quadra 650, sold by Apple just before the transition to PowerPC architecture, served as an ideal platform for this project, as it originally operated on the 68040 processor. A custom adapter developed by [Reinauer] made it possible to connect the two processors, paving the way for this groundbreaking upgrade.
While the hardware upgrade was a significant step, the software compatibility posed a challenge. The 68060 is not fully compatible with the 68040’s instruction set, complicating the installation of System 7.1, the last version that could run on these machines. [zigzagjoe] successfully integrated a translation layer into a custom ROM, enabling the Mac to boot and install the operating system.
Despite achieving this milestone, the performance of the 68060 at its full clock speed of 66 MHz proved unstable. To ensure reliable operation, [zigzagjoe] clocked the CPU down to 50 MHz. This change still represents a significant leap from the original 25 MHz of the 68040 in the Quadra 650. Notably, at 66 MHz, the system managed to run the classic game DOOM at 16.4 FPS, although performance dropped to 14.3 FPS at the more stable clock speed.
Even as Apple moved on from the 68k architecture to embrace PowerPC and later x86 and ARM technologies, the passion of enthusiasts like [zigzagjoe] demonstrates the ongoing interest in retro computing. This achievement not only highlights the ingenuity of the community but also raises questions about the potential for further advancements in Macintosh hardware. The ability to run DOOM on this new setup answers a fundamental question for retro computing enthusiasts: can it run classic software? The answer, as proven, is a resounding yes.
As the retro computing scene continues to thrive, this milestone serves as a reminder of the rich history and ongoing innovation in the world of personal computing.
