PowerPC Processors Supported by Mac OS 9

Mac OS 9, the final release of the classic Macintosh operating system, ran exclusively on computers powered by PowerPC processors. Across its lifecycle from version 9.0 to 9.2.2, Apple officially supported several generations of PowerPC processor families, including the PowerPC 601, 603, 604, G3 (750), and G4 (74xx) series. However, hardware requirements tightened as update revisions were released, eventually limiting support exclusively to G3 and G4 architectures.

PowerPC 601

The first-generation PowerPC 601 processor was officially supported in early versions of Mac OS 9.0 and 9.0.4. It was found in early Power Macintosh models such as the Power Mac 6100, 7100, and 8100. Official support for the PowerPC 601 was dropped entirely with the release of Mac OS 9.1.

PowerPC 603 and 603e

The low-power PowerPC 603 and its updated 603e variant were designed primarily for budget desktops and early PowerBook laptops (such as the PowerBook 5300, 1400, and 3400c, as well as Performa models). Mac OS 9 officially supported these chips through Mac OS 9.1, but dropped them in Mac OS 9.2.

PowerPC 604, 604e, and 604ev

Targeted at high-performance workstations, the PowerPC 604 family was used in mid-to-late 1990s Power Mac towers, including the 7300, 8500, 8600, and 9600 series. Like the 603 series, the 604 family was officially supported through Mac OS 9.1, after which it was phased out.

PowerPC G3 (750 / 740)

The third-generation PowerPC G3 processor line was fully supported across the entire lifespan of Mac OS 9, from version 9.0 through 9.2.2. Systems utilizing this architecture included the beige and Blue and White Power Macintosh G3, the original iMac lines, the iBook, and the PowerBook G3 series.

PowerPC G4 (7400, 7410, 7450, 7455)

The fourth-generation PowerPC G4 architecture was fully supported by Mac OS 9. It debuted with Mac OS 9.0 systems and remained supported through Mac OS 9.2.2. The G4 architecture was used across Power Mac G4 towers, PowerBook G4 laptops, the iMac G4, and the eMac. Certain late-model G4 Macs could not boot natively into Mac OS 9, but could still run it inside the Mac OS X "Classic Environment."

Version Compatibility Summary

• Mac OS 9.0 to 9.0.4: Officially supported PowerPC 601, 603/603e, 604/604e, G3, and G4.
• Mac OS 9.1: Officially supported PowerPC 603/603e, 604/604e, G3, and G4 (PowerPC 601 dropped).
• Mac OS 9.2 to 9.2.2: Officially supported only PowerPC G3 and G4 architectures (PowerPC 603 and 604 dropped).

Unsupported Architectures

The 64-bit PowerPC 970 (PowerPC G5) was never officially supported by Mac OS 9; G5-based Macs required Mac OS X and were completely incapable of booting Mac OS 9. Additionally, legacy Motorola 68k processors were not supported natively, having been phased out with Mac OS 8.5.