Apple Macintosh 512K

Apple Macintosh 512K was introduced in 10 September 1984 as the higher-memory development of the original compact Macintosh, widely nicknamed the Fat Mac. It used a Motorola 68000 at 7.8336 MHz with 512KB. 512KB RAM removed the original Macintosh's most severe limitation.

Four times the RAM made larger applications, networking and practical disk-based work possible while preserving the original form.

Notable Features

• 512KB RAM removed the original Macintosh's most severe limitation.
• The unchanged enclosure maintained complete compatibility with compact-Mac accessories.
• AppleTalk support helped the model enter offices and schools.

Historical Significance

• Four times the RAM made larger applications, networking and practical disk-based work possible while preserving the original form.
• Its place in the range reflects Apple's progression from the original compact Macintosh toward broader professional, educational and portable markets.

Collector’s Notes

• Many 128K machines were upgraded, so board identity and rear labels should be checked
• Original keyboards, mice, storage devices and model-specific accessories help document a complete period configuration.

Specifications

Technical Information
Name	Apple Macintosh 512K
Manufacturer	Apple
Launched	Monday, September 10, 1984
Country	United States
CPU	Motorola 68000 at 7.8336 MHz
Units Sold
Operating System	Classic Macintosh System Software
I/O	Two serial, mouse, keyboard, external floppy and audio ports
Keyboard	External compact keyboard and one-button mouse
Storage	Built-in 400KB 3.5-inch floppy drive
Sound	Four-voice 8-bit mono sound
Graphics	512 x 342 one-bit bitmapped graphics
Display	Built-in 9-inch 512 x 342 monochrome display
ROM	64KB Macintosh ROM
RAM	512KB
CPU Speed	7.8336 MHz