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Macintosh Quadra 900

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Macintosh Quadra 900 in front
Macintosh Quadra 900

Macintosh Quadra 900
DeveloperApple Computer
Product familyMacintosh Quadra
Release dateOctober 21, 1991 (1991-10-21)
Introductory priceUS$7,200 (equivalent to $16,110 in 2023)
DiscontinuedMay 18, 1992 (1992-05-18)
Operating systemSystem 7.0.1Mac OS 8.1
CPUMotorola 68040 @ 25 MHz
Memory4 MB, expandable to 256 MB (80 ns 30-pin SIMM)
DimensionsHeight: 18.6 in (47.25 cm)
Width: 8.9 in (22.6 cm)
Depth: 20.6 in (52.32 cm)
Mass36.8 pounds (16.7 kg)
PredecessorMacintosh IIfx
SuccessorMacintosh Quadra 950
RelatedMacintosh Quadra 700

The Macintosh Quadra 900 is a personal computer designed, manufactured, and sold by Apple Computer from October 1991 to May 1992. It was introduced alongside the Quadra 700 as the first computers in the Quadra family of Macintosh computers using the Motorola 68040 processor.[1] It is also the first computer from Apple to be housed in an 18.6 inch (47 cm) tall mid-tower form factor, which by 1991 had gained momentum with PC manufacturers as a suitable design for departmental servers.

The Quadra 900 had a short lifespan; it was discontinued about six months after the first shipments in favor of the more powerful Quadra 950.



The Quadra 900 was more expandable than the Quadra 700 but cost US$7,200.[1] The Quadra 900 could be upgraded to 256 megabytes of RAM,[2] an astronomical amount for the time, when a typical midrange system would come equipped with 2–4 MB. The standard, as-shipped configuration for the 900 was 4 MB. The high RAM and storage capacity, along with the expandability of five NuBus 90 slots and fast 25 MHz processor, made it a very useful computer for scientific or design work. The mid-tower case design features a single 5.25-inch drive bay initially intended to hold a tape backup drive, but was often repurposed to hold a CD-ROM or SyQuest drive during the model's operational lifespan. Featuring 16 slots for 30-pin SIMMs (installed in groups of four),[2] Quadra 900s with full complements of RAM were exceedingly rare due to the high cost (many thousands of dollars) of the SIMMs at the time.

A new three-mode key-lock system on the front panel can be set to Off, On, and Secure. When set to Off, the machine can't be powered up. In Secure mode, the floppy drive and ADB port are disabled, offering a degree of local protection.[3]

System 7.0.1 was included and supports up to Mac OS 8.1. It is the earliest Macintosh model with the ability to run Mac OS 8.[citation needed]

With the Power Macintosh Upgrade Card installed, the Quadra 900 runs at 50 MHz and its name is reported in the System Profiler as the Power Macintosh 900.[4]


  • Processor: 25 MHz Motorola 68040
  • Processor Cache: 8 KB Level 1
  • Bus Speed: 25 MHz
  • Hard Drive: 160 or 400 MB
  • Media drives: 1.44 MB floppy drive with one 5.25" SCSI drive bay available
  • Software: Mac OS 7.0.1 - 8.1
  • Logicboard RAM: None
  • Maximum RAM: 256 MB
  • Type of RAM: 30-pin SIMM (16 slots)
  • Minimum RAM Speed: 80 ns
  • Interleaving Support: No
  • Graphics: Integrated
  • Display Connection: DB-15
  • Graphics Memory: 1 MB standard, upgradable to 2 MB via 4 VRAM slots
  • Expansion Slots: 5 - NuBus, 1 - PDS
  • Hard Drive Bus: SCSI
  • Backup Battery: 3.6 V Lithium
  • Max Watts: 303 W
  • Ports: AAUI-15 Ethernet, 1 ADB, DB-25 SCSI, 2 Serial, 3.5-mm mono input jack, 3.5-mm stereo output jack


Timeline of Macintosh Centris, LC, Performa, and Quadra models, colored by CPU type
Macintosh Performa 6214Macintosh Performa 6210Macintosh Performa 6205Macintosh Performa 6230Macintosh Performa 6220Macintosh Quadra 840AVMacintosh Quadra 650Macintosh Quadra 610Macintosh Quadra 605Macintosh Quadra 660AVMacintosh Quadra 800Macintosh Centris 650Macintosh Centris 610Macintosh Quadra 950Macintosh Quadra 630Macintosh Quadra 900Macintosh Quadra 700Macintosh Performa 6420Macintosh Performa 6410Macintosh Performa 5440Macintosh Performa 5430Macintosh Performa 5280Macintosh Performa 6360Macintosh Performa 5260Macintosh Performa 6400Macintosh Performa 6400Macintosh Performa 5400Macintosh Performa 5400Macintosh Performa 6260Macintosh Performa 5400Macintosh Performa 5420Macintosh Performa 5410Macintosh Performa 5270Macintosh Performa 5260Macintosh Performa 6320Macintosh Performa 6310Macintosh Performa 6300Macintosh Performa 6290Macintosh Performa 5320Macintosh Performa 5300Macintosh Performa 6218Macintosh Performa 6216Macintosh Performa 6200Macintosh Performa 6116Macintosh Performa 5220Macintosh Performa 5215Macintosh Performa 5210Macintosh Performa 5200Macintosh Performa 640CDMacintosh Performa 580CDMacintosh Performa 588CDMacintosh Performa 638Macintosh Performa 637Macintosh Performa 636Macintosh Performa 635Macintosh Performa 631Macintosh Performa 630Macintosh Performa 578Macintosh Performa 577Macintosh Performa 575Macintosh Performa 476Macintosh Performa 475Macintosh Performa 560Macintosh Performa 550Macintosh Performa 275Macintosh Performa 6118Macintosh Performa 6117Macintosh Performa 6115Macintosh Performa 6112Macintosh Performa 6110Macintosh Performa 467Macintosh Performa 466Macintosh Performa 460Macintosh Performa 410Macintosh Performa 520Macintosh Performa 450Macintosh Performa 430Macintosh Performa 405Macintosh Performa 250Macintosh Performa 600Macintosh Performa 400Macintosh Performa 200Power Macintosh 5300 LCMacintosh LC 575Macintosh TVMacintosh LC IIIMacintosh LC 550Macintosh LC 580Macintosh LC 520Macintosh LC 630Macintosh LC 475Power Macintosh 5200 LCMacintosh LC IIIMacintosh LC IIMacintosh LC


  1. ^ a b Webster, Bruce F. (December 1991). "Macintosh Quadras - Power But No Pizzazz". Macworld. Vol. 8, no. 12. pp. 140–147.
  2. ^ a b c "Macintosh Quadra 900: Technical Specifications". Apple.
  3. ^ Pogue, David; Schorr, Joseph (1999). "Chapter 12: From 128K to Quadra: Mac to Mac". MacWorld Mac Secrets, 5th Edition. IDG Books. pp. 483-484. ISBN 0-7645-4040-8.
  4. ^ "Quadra 900: Technical Specifications". Apple.