The Macintosh 512K Personal Computer, the second of a long line of Apple Macintosh computers, was the first update to the original Macintosh 128K. It was virtually identical to the previous Mac, differing primarily in the amount of built-in memory (RAM), which quadrupled the original's. This large increase earned it the nickname Fat Mac. The additional memory was significant because more ambitious users with computer experience stretched the capacity of the original Mac almost immediately, despite the limited number of applications.

Like the 128K Macintosh before it, the 512K contained an 8 MHz Motorola 68000 connected to a 512 KB DRAM by a 16-bit data bus. Though the memory had been quadrupled, it could not be upgraded. A 64 KB ROM chip boosts the effective memory to 576 KB, but this is offset by the display's 22 KB framebuffer, which is shared with the DMA video controller. It shared a revised logicboard with the re-badged Macintosh 128K (previously just called the Macintosh), which streamlined manufacturing.

It sold for $3,195, and was replaced in April 1986 by the 512Ke

Processor

CPU: Motorola MC68000
CPU Speed: 8 MHz
Bus Speed: 8 MHz
Data Path Width: 16 bit
Address Width: 16 bit
ROM: 64 kB
Onboard RAM: 512 kB
Maximum RAM: 512 kB
Level 1 Cache: 0.5 kB

Power: 60 Watts
Dimensions: 13.6" H x 9.6" W x 10.9" D
Weight: 16.5 lbs.

Manufacturer: Apple
Date: 9th October 1984

This exhibit has a reference ID of CH6093. Please quote this reference ID in any communication with the Centre for Computing History.