The Macintosh Quadra 605 (also sold as the Macintosh LC 475 and Macintosh Performa 475) is a

personal computer A personal computer, commonly referred to as PC or computer, is a computer designed for individual use. It is typically used for tasks such as Word processor, word processing, web browser, internet browsing, email, multimedia playback, and PC ...

designed, manufactured, and sold by

Apple Computer Apple Inc. is an American multinational corporation and technology company headquartered in Cupertino, California, in Silicon Valley. It is best known for its consumer electronics, software, and services. Founded in 1976 as Apple Computer Co ...

from October 1993 to July 1996. The model names reflect a decision made at Apple in 1993 to follow an emerging industry trend of naming product families for their target customers Quadra for business, LC for education, and

Performa The Macintosh Performa is a family of personal computers designed, manufactured and sold by Apple Computer, Inc. from 1992 to 1997. The Performa brand re-used models from Apple's Quadra, Centris, LC, Classic, and Power Macintosh families ...

for home. Accordingly, the Performa 475 and 476 was sold in

department store A department store is a retail establishment offering a wide range of consumer goods in different areas of the store under one roof, each area ("department") specializing in a product category. In modern major cities, the department store mad ...

s and electronics stores such as

Circuit City Circuit City Corporation, Inc., formerly Circuit City Stores, Inc., is an American consumer electronics retail company, which was founded in 1949 by Samuel Wurtzel as the Wards Company, operated stores across the United States, and pioneered th ...

, whereas the Quadra was purchased through an authorized Apple reseller. When introduced, the Quadra 605 was the least expensive new computer in Apple's lineup. (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 The Macintosh LC II is a personal computer designed, manufactured, and sold by Apple Computer from March 1992 to March 1993. The LC II succeeded the LC which would be discontinued, replacing its Motorola 68020 processor with a 68030 and incre ...

with a 16 MHz 68030 processor.) The Quadra 605 reuses the

Macintosh LC III The Macintosh LC III is a personal computer designed, manufactured, and sold by Apple Computer from February 1993 to February 1994. It replaced the commercially successful Macintosh LC II in Apple's lineup of mid-class computers, and was signi ...

pizza box form factor In computing, a pizza box is a style of case design for desktop computers or network switches. Pizza box cases tend to be wide and flat, normally in height, resembling pizza delivery boxes and thus the name. This is in contrast to a tower sy ...

with minor modifications. 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 until the

Mac Mini Mac Mini (stylized as Mac mini) is a small form factor (desktop and motherboard), small form factor desktop computer developed and marketed by Apple Inc. It is one of the company's four current Mac (computer), Mac desktop computers, positioned ...

, nearly ten years later.

Models

All models come standard with a

Motorola 68LC040 The Motorola 68040 ("''sixty-eight-oh-forty''") is a 32-bit microprocessor in the Motorola 68000 series, released in 1990. It is the successor to the 68030 and is followed by the 68060, skipping the 68050. In keeping with general Motorola ...

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 A processor direct slot (PDS) is a slot incorporated into many older Macintosh models that allowed direct access to the signal pins of a CPU, similar to the functionality of a local bus in PCs. This would result in much higher speeds than having ...

, 1 ADB and 2 serial ports, external SCSI port, and a manual-inject floppy drive. Introduced October 18, 1993: * Macintosh Performa 475: 4 MB RAM, 160 MB HDD. Bundled with a keyboard and Apple Color Plus 14" Display. * Macintosh Performa 476: 4 MB RAM, 230 MB HDD. Bundled with a keyboard and Apple Color Plus 14" Display. Introduced October 21, 1993: * Macintosh Quadra 605: 4 MB RAM, 80 MB HDD. Slightly different case design, the only variant that does not have a case screw. Not available in Europe. * Macintosh LC 475: 4 MB RAM, 80 MB HDD. Bundled with a keyboard and optionally with an Apple Macintosh Color Display; Education market only.

Hardware

Central processing unit A central processing unit (CPU), also called a central processor, main processor, or just processor, is the primary Processor (computing), processor in a given computer. Its electronic circuitry executes Instruction (computing), instructions ...

: 25

MHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base u ...

MC68LC040, 32-bit bus. 8 KB of on-chip L1

cache Cache, caching, or caché may refer to: Science and technology * Cache (computing), a technique used in computer storage for easier data access * Cache (biology) or hoarding, a food storing behavior of animals * Cache (archaeology), artifacts p ...

is divided into 4 KB of ''data'' and 4 KB of ''instruction'' cache. There are no other caches, although an L2 cache is possible via an LC PDS card. The 68LC040 can be replaced with a 68040 which includes onboard

Floating Point Unit A floating-point unit (FPU), numeric processing unit (NPU), colloquially math coprocessor, is a part of a computer system specially designed to carry out operations on floating-point numbers. Typical operations are addition, subtraction, multipli ...

. This will approximately triple the speed of floating point operations.Lowendmac.com: Mac Benchmarks - Quadra 605 a.k.a. LC 475, Performa 475 or 476
.

Random-access memory Random-access memory (RAM; ) is a form of Computer memory, electronic computer memory that can be read and changed in any order, typically used to store working Data (computing), data and machine code. A random-access memory device allows ...

: 4 MB on the motherboard, one 72-pin SIMM socket for 80 ns or faster SIMMs. The official supported maximum RAM is 36 MB in one 32 MB 72-pin SIMM plus 4 MB on the motherboard, but larger SIMMs do work—up to 128 MB may be used, with some limits on RAM type.Lowendmac.com: Quadra 605
. Quadra 605s work with single-banked SIMMs (Note that single-banked is a logic-level trait, not a physical one; single-banked SIMMs may be single or double sided). Physical limits might apply if the side of the SIMM facing the CPU has thicker chips, as the clips on the SIMM socket will not close around it automatically. It should be possible to manually push the clips enough to hold the SIMM in place. The DJMEMC memory controller used in the Quadra 605's predecessors (Quadra/Centris 610, Quadra/Centris 650 and Quadra 800) will only recognize SIMMs up to 32 MB, while the newer MEMCjr used in the Quadra 605 recognizes the larger sizes. Video: Video out is provided by one DA15F connector, and is compatible with VGA monitors through the use of an adaptor.Apple.com: VGA Monitors - Which Macintosh Models Are Compatible
. Two internal

Video RAM Video random-access memory (VRAM) is dedicated computer memory used to store the pixels and other graphics data as a framebuffer to be rendered on a computer monitor. It often uses a different technology than other computer memory, in order to b ...

slots can take either two 256 KB 80 ns 68-pin VRAM SIMMs, or two 512 KB SIMMs. Installing one 512 KB and one 256 KB VRAM SIMM garbles the display. Resolutions and colors available with the two VRAM configurations are shown in the table below: Audio: * Out: stereo 8-bit, 11 kHz or 22 kHz; this is the first Macintosh LC model to support stereo output * In: Line-level. The input socket is a stereo socket, and can input two channels of a stereo signal—however, these are mixed and only accessible to the hardware as a combined mono 8-bit signal. An Apple PlainTalk Microphone provides line-level input by using a longer 4-contact plug which receives power from a 5 V supply within the input jack. Other microphones only give a mic-level input, and do not work with the Quadra 605. Recording is possible at 11,025 or 22,050 samples/second, with filters applied at 3.5 kHz and 7 kHz, respectively, while recording.Apple.com: Developer Note - Macintosh LC 475 and Macintosh Quadra 605
Floppy Drive: 1.4 MB SuperDrive, manual-inject. Hard Drive: 80 MB, 160 MB or 230 MB

SCSI Small Computer System Interface (SCSI, ) is a set of standards for physically connecting and transferring data between computers and peripheral devices, best known for its use with storage devices such as hard disk drives. SCSI was introduced ...

hard drive, depending on model. Battery: Quadra 605s take a lithium half-AA cell 3.6 V battery. If the battery is drained, the video will not start up. To start up a Quadra 605 with a flat or missing battery, it can be turned on for a few seconds, then turned off for a second then on again. This leaves enough charge in the system's capacitors for video to start up. Power supply: 30 watts standard, but many second-hand machines come with replacement PSUs, either third-party, Apple replacement, or stripped from earlier LC models. Some of these go up to 45 watts. The Quadra 605 is a registered

Energy Star Energy Star (trademarked ENERGY STAR) is an Efficient energy use, energy-efficiency program established in 1992. It is administered by the U.S. Environmental Protection Agency (EPA) in partnership with the U.S. Department of Energy (DOE). The EPA ...

-Compliant product. Weight: 8.8 lb / 4 kg standard. A Quadra 605 can support a monitor up to 35 lb / 15.9 kg.Apple.com: Desktop Macintosh Computers: How Much Mass (Weight) Can They Support?
. Dimensions: 2.9 " high × 12.2" wide × 15.3" deep / 7.4 cm high × 31 cm wide × 38.8 cm deep.

Expansion

The Quadra 605 contains one LC III-style 68030-compatible LC

. While this is mechanically compatible with previous models' LC PDS (it will take 96-pin or 114-pin LC PDS slot cards) it is not a true LC PDS,Apple.com: LC 475, Performa 475 & 476, Quadra 605 - Expansion Slot
. but emulates the previous machine's 68030 slot. 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.
. 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. In addition it can utilize the

Apple IIe Card The Apple IIe Card is a compatibility card, which through hardware and software emulation, allows certain Macintosh computers to run software designed for the Apple II (excluding the 16-bit Apple IIGS, IIGS). Released in March 1991 for use w ...

, which allows the 605 to emulate an

Apple IIe The Apple IIe (styled as Apple //e) is the third model in the Apple II series of personal computers produced by Apple Inc., Apple Computer. It was released in January 1983 as the successor to the Apple II Plus. The ''e'' in the name stands for ...

. The Quadra 605 has one

bus, with a 50-pin internal connector (with space for one low-profile 3.5" SCSI device) and one 25-pin DB25F external connector. SCSI is provided by an NCR 53C96 controller, which can achieve 6 MB/s internally with a fast enough drive, or 4 MB/s externally.Apple.com: Macintosh - SCSI Data Transfer Rates
. Two serial ports are provided on a Quadra 605; one 8-pin

Mini-DIN The mini-DIN connectors are a family of multi-pin electrical connectors used in a variety of applications. Mini-DIN is similar to the larger, older 13.2 mm diameter DIN connector. Design Mini-DIN connectors are in diameter and come in s ...

printer port and one 9-pin Mini-DIN modem port similar to the printer port, but with an extra pin to supply +5 V power from the ADB power supply. Apple recommends no more than 100 mA should be drawn from this pin.Apple.com: LC 475, Quadra 605, Performa 475 476 - Serial Ports
. The Quadra 605, like most other Macintoshes manufactured before 1999, includes an

Apple Desktop Bus Apple Desktop Bus (ADB) is a proprietary bit-serial peripheral bus connecting low-speed devices to computers. It was introduced on the Apple IIGS in 1986 as a way to support low-cost devices like keyboards and mice, enabling them to be conn ...

port for use with a

keyboard Keyboard may refer to: Text input * Keyboard, part of a typewriter * Computer keyboard ** Keyboard layout, the software control of computer keyboards and their mapping ** Keyboard technology, computer keyboard hardware and firmware Music * Mus ...

and

mouse A mouse (: mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus'' ...

or other low-speed, low-power

peripheral A peripheral device, or simply peripheral, is an auxiliary hardware device that a computer uses to transfer information externally. A peripheral is a hardware component that is accessible to and controlled by a computer but is not a core compo ...

s. Some earlier models also contain a ROM SIMM socket, located just to the left of the VRAM. No SIMMs were made for this slot, and most boards only contain the solder pads indicating its position. The ROMs as used in production machines are two surface mount chips located directly behind the CPU. Quadra 605s use a 1024 KB ROM,Apple.com: Macintosh - ROM Size for Various Models
. version 7C.
.

PowerPC upgrades

The Quadra 605 was compatible with Apple's

Macintosh Processor Upgrade Card The generically named Macintosh Processor Upgrade Card (code named STP) is a central processing unit upgrade card sold by Apple Computer, designed for many Motorola 68040-powered Macintosh LC, Quadra and Performa models. The card contains a Pow ...

which provided a 50 MHz PowerPC 601 CPU.

DayStar Digital DayStar Digital, Inc., was a company founded in 1983 by Andrew Lewis as a subcontract manufacturer of electronic assemblies and circuit boards. In 1986, the company released memory upgrades for Mac (computer), Apple Macintosh (Mac) computers as i ...

and

Sonnet A sonnet is a fixed poetic form with a structure traditionally consisting of fourteen lines adhering to a set Rhyme scheme, rhyming scheme. The term derives from the Italian word ''sonetto'' (, from the Latin word ''sonus'', ). Originating in ...

manufactured 100 MHz versions of this card which could also be used in the Quadra 605. These upgrade cards plug directly into the 68040 socket, but when fitted cover the LC PDS expansion slot, making this slot unavailable for other expansion cards.

Miscellaneous

Some Quadra 605s have a Cuda reset switch which is used to manually reset the PRAM, located towards the rear of the motherboard just to the front of the audio out port and labeled "S1". Others do not include this switch, instead having two solder pads within a silkscreened square. The keyboard power-on key will not start up a Quadra 605 as there is no soft power-on. Only the rocker switch at the back will turn a Quadra 605 on or off. 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. Quadra 605s have no reset button or programmer's button, but key combinations can perform the same functions. To reset, users can hold down the Command, Control and Power keys. For a programmer's button click, users can hold down the Command and Power keys.Apple.com: Desktop Macintosh - Power, Reset, and Interrupt Buttons
. 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 The Apple Interactive Television Box (AITB) was a television set-top box developed by Apple Computer (now Apple Inc.) in partnership with a number of global telecommunications firms, including British Telecom and Belgacom. Prototypes of the ...

prototypes. Later prototypes used their own board design, but still retained a resemblance to the 605.

Gestalt IDs

The standard Gestalt ID for a 25 MHz Quadra 605 is 94.Apple.com: Macintosh Computers - Gestalt ID Codes
. The ID of the logic board that the Quadra 605 shares with other LC/Performa models depends on two things. Jumper J18 (located just behind the hard drive) will identify the computer as a Quadra 605 (ID 94 @ 25 MHz) if it is ON, and as an LC475/Performa 47x (ID 89 @ 25 MHz) if it is OFF. Over-clocking and under-clocking the motherboard also changes the Gestalt ID. A list of Gestalt IDs returned with various logic board modifications (speed as reported by Newer Technology's "Clockometer") are as follows

Overclocking

Overclocking the Quadra 605 family of machines has been historically popular, with many users undertaking a simple resistor mod to increase the computer's speed to 33MHz from the standard 25MHz, ww.applefool.com/clockchipping/q605.html applefool.com: Clock Chipping - Q605 (LC475, P475, P476) Speedup. with higher speeds available by injecting an alternative clock source instead of the onboard clock.applefool.com: Clock Chipping - Q605 (LC475, P475, P476) Speedup to 40MHz w/o external oscillator
. In 2024 it was discovered that the onboard clock generator was actually directly programmable through software, allowing a range of speeds to be selected with no hardware modifications, often up to bus speeds of 40MHz.68kmla.org: Overclock LC475 P475 Q605 Without Soldering
Further speed and stability improvements can be made by moving the resistor which selects the SCSI chip's clock from the location which uses the bus frequency68kmla.org: Quadra 605 Freezing
to the location that uses half the bus frequency, by replacing the CPU with a higher speed grade part, and by replacing the MC88920 chip (which produces a number of clock outputs for distribution around the logic board based on the input from the clock generator) with a compatible, higher speed grade, MC88916. Faster RAM, ROM and VRAM is only likely needed if attempting overclocks beyond 50MHz as the software adds wait states to compensate for higher clock speeds. As they use the same chipset, the software also works with the

LC 575 LC or Lc may refer to: Arts and entertainment * Library of Congress Classification, a system of library classification Gaming and play * Lego Chess, a Lego-based chess video game * Lego City, a theme of Lego * Lego Creator, a theme of Lego * ' ...

family of All-In-One macs.

System software

A standard Quadra 605 is capable of running

classic Mac OS Mac OS (originally System Software; retronym: Classic Mac OS) is the series of operating systems developed for the Mac (computer), Macintosh family of personal computers by Apple Computer, Inc. from 1984 to 2001, starting with System 1 and end ...

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. With a PowerPC upgrade installed, it can run 8.5, 8.5.1, 8.6, 9.0, 9.0.1, 9.0.2, 9.0.3, 9.0.4 and 9.1. Versions of the System Software below 7.5 require the use of

System Enabler A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment, is described by its boundaries, structure and purpose and is exp ...

065.Apple.com: System Enablers - Current Versions & Change History
. If a Quadra 605 is running a version of System 7.1, over-clocking it from the standard 25 MHz to 33 MHz will change the Gestalt ID, but the enabler will recognize the new ID. Under-clocking to 20 MHz, however, will change the Gestalt ID to one the enabler doesn't recognize as compatible, and the system won't boot. System 7.5 or later is not affected by this issue.

Timeline

References

External links

at lowendmac.com

Quadra 605 at apple-history.com
{{Apple hardware before 1998

605 Year 605 ( DCV) was a common year starting on Friday of the Julian calendar. The denomination 605 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming yea ...

0605 Quadra 605 Quadra 605 Quadra 605 Quadra 605 Computer-related introductions in 1993 Products and services discontinued in 1994 Products and services discontinued in 1996