(The Performa 410, introduced at the same time, at the same price of about US$1,000, which included a monitor, was based on the much older Macintosh LC II with a 16 MHz 68030 processor.

)[3] The Quadra 605 reuses the Macintosh LC III's pizza box form factor with minor modifications.

[4] The Quadra 605 was discontinued in October 1994, and the LC 475 variant continued to be sold to schools until July 1996.

Apple offered no direct replacement for these machines, making it the final Macintosh to use the LC's lightweight slim-line form factor.

Apple would not release another desktop computer under 10 pounds (4.5 kg) until the Mac Mini, nearly ten years later.

All models come standard with a Motorola 68LC040 CPU running at 25 MHz, 4 MB RAM on board, 512 KB of VRAM (expandable to 1 MB), 1 LC III-style Processor Direct Slot, 1 ADB and 2 serial ports, external SCSI port, and a manual-inject floppy drive.

Due to the success of the LC PDS in earlier Macs and with many expansion options already manufactured, Apple kept the same slot type in these 68040 machines.

[17] While the Quadra 605's LC PDS is mostly 68030-compatible, expansion cards made specifically for '030 processors, such as 68881 or 68882 FPUs, will not work.

[19] The Quadra 605, like most other Macintoshes manufactured before 1999, includes an Apple Desktop Bus port for use with a keyboard and mouse or other low-speed, low-power peripherals.

[21] The Quadra 605 was compatible with Apple's Macintosh Processor Upgrade Card which provided a 50 MHz PowerPC 601 CPU.

Pressing the power-on key while booted is the same as selecting the Shut Down command in the Finder, and once a Quadra 605 has completed its shutdown process it will prompt the operator to manually turn it off.

[25] There are some hard crash situations where even this is not enough to restore the system, in which case the power switch is the only recourse.

A modified Quadra 605 motherboard was used as the basis of early Apple Interactive Television Box prototypes.

A list of Gestalt IDs returned with various logic board modifications (speed as reported by Newer Technology's "Clockometer") are as follows A standard Quadra 605 is capable of running classic Mac OS versions 7.1, 7.1.1 (Pro), 7.5, 7.5.1, 7.5.3, 7.5.5, 7.6, 7.6.1, 8.0, and 8.1.