Apple Macintosh Quadra 900

Apple Macintosh Quadra 900 was introduced in 21 October 1991 as Apple's first full-size 68040 tower workstation with extensive memory and storage capacity. It used a Motorola 68040 at 25 MHz with 4MB standard; expandable to 256MB. Sixteen memory sockets supported up to 256MB.

Five NuBus slots and sixteen SIMM sockets targeted publishing, server and scientific installations needing exceptional expansion.

Notable Features

• Sixteen memory sockets supported up to 256MB.
• Five NuBus slots provided more expansion than other Quadras.
• Key-locking tower enclosure offered multiple internal drive bays.

Historical Significance

• Five NuBus slots and sixteen SIMM sockets targeted publishing, server and scientific installations needing exceptional expansion.
• Its place in the range reflects Apple's progression from the original compact Macintosh toward broader professional, educational and portable markets.

Collector’s Notes

• Complete tower plastics, key and drive carriers are valuable because replacements are scarce
• Original keyboards, mice, storage devices and model-specific accessories help document a complete period configuration.

Specifications

Technical Information
Name	Apple Macintosh Quadra 900
Manufacturer	Apple
Launched	Monday, October 21, 1991
Country	United States
CPU	Motorola 68040 at 25 MHz
Units Sold
Operating System	System 7.0.1 through Mac OS 8.1
I/O	Video, SCSI, two serial, ADB, audio, Ethernet and five NuBus slots
Keyboard	External ADB keyboard and mouse
Storage	1.44MB floppy with multiple internal SCSI bays
Sound	Eight-bit mono input and stereo output
Graphics	High-resolution colour graphics
Display	External or built-in-video-supported monitor
ROM	1MB ROM
RAM	4MB standard; expandable to 256MB
CPU Speed	25 MHz