Quantum Effect Devices

Quantum Effect Devices, Inc.
Company type	Public (before acquisition)
Industry	Semiconductor, Microprocessor design
Predecessor	Quantum Effect Design
Founded	1991; 35 years ago in Palo Alto, California, United States
Founder	Tom Riordan, Earl Killian, Ray Kunita
Defunct	2000
Fate	Acquired by PMC-Sierra
Successor	PMC-Sierra Microprocessor Products Division
Headquarters	Palo Alto, United States
Area served	Worldwide
Key people	Tom Riordan (founder)
Products	MIPS microprocessors (R4600, R4700, R4650, R5000, RM5200, RM7000, RM9000 series), PowerPC 603q (prototype)
Parent	PMC-Sierra (after 2000)

Quantum Effect Devices, Inc. (QED) was a microprocessor design firm established in 1991 under the name Quantum Effect Design in Palo Alto, California.

History

The company was founded by Tom Riordan, Earl Killian, and Ray Kunita, who previously held senior management positions at MIPS Computer Systems Inc.. They departed as MIPS shifted focus from microprocessor design—their core expertise—to attempting to market full computer systems. Shortly thereafter, MIPS was acquired by SGI. Initial financing and customer support for QED’s early designs came from IDT.

Business

QED’s original goal was to create a MIPS microprocessor tailored for laptop computers as part of the ACE initiative, which aimed to support multiple RISC architectures on Windows NT. While firms such as DeskStation Technology and ShaBLAMM! Computer tried to develop RISC-based personal computers, the anticipated market demand did not emerge. Nevertheless, QED’s debut product, the R4600 "Orion" microprocessor, found success in embedded sectors like networking routers and arcade gaming machines. Subsequent microprocessor models were developed for customers including Toshiba, IDT (R4700), IDT & NKK (R4650), and SGI & NEC (R5000).

The PowerPC 603q chip, designed in collaboration with Motorola for Apple Computer's intended home PC and gaming devices, never reached mass production.

To increase revenue streams, QED evolved into a product company marketing its own MIPS microprocessors and adopted the name Quantum Effect Devices. Successful releases such as the RM5200 and RM7000 under the "RISCMark" brand preceded its initial public offering on February 1, 2000. The stock debuted at $16 per share and quickly climbed to $56.50 on opening day. In October 2000, PMC-Sierra acquired QED through a stock transaction valued around $2.3 billion. Following the acquisition, QED became PMC's Microprocessor Products Division and completed the RM9x00 series; however, these products did not meet commercial expectations. Between 2005 and 2006, PMC-Sierra laid off most of the original microprocessor core team.

The company’s name stemmed from Tom Riordan’s foresight that semiconductor miniaturization would eventually reach scales where quantum effects significantly impact circuit performance.

Devices

QED’s inaugural microprocessor, the R4600, was a streamlined redesign of the classic 5-stage RISC pipeline featuring large caches aimed at providing superior cost-to-performance compared to the more complex R4000. Although initially intended for MIPS-based laptops, it achieved market penetration primarily in embedded applications such as routers produced by Cisco Systems and arcade games developed by Atari/Midway like Killer Instinct. Manufacturing and sales licenses for the R4600 were granted to IDT and Toshiba.

The R4700 was developed with SGI in mind to enhance floating-point operation efficiency by improving multiply instruction throughput. It powered SGI's Indy workstation and was licensed to both IDT and Toshiba.

Commissioned by NKK, the R4650 offered a more economical design featuring reduced cache sizes and single-precision floating-point capabilities while introducing multiply–accumulate instructions beneficial for applications such as software modems. This processor was utilized in Microsoft’s original WebTV device and licensed to IDT and NKK. The R4640 variant featured a 32-bit system bus derived from the R4650 architecture.

Designed at SGI’s request, the R5000 incorporated doubled 32 KB instruction and data caches along with a fully pipelined floating-point unit supporting multiply–accumulate operations and limited superscalar instruction dispatch. It powered SGI’s entry-level workstations including the SGI O2 and Indy models. Ownership of this design resided with SGI who licensed it to IDT, NEC, and eventually Toshiba.

The PowerPC 603q processor was commissioned by Motorola targeting Apple’s affordable computing segments such as a student-oriented home computer and the Pippen game console. Essentially an adaptation of the R4600 pipeline to PowerPC instruction sets, it emphasized cost-effectiveness and low power consumption. Development ceased after Apple canceled related projects despite having functional silicon prototypes.

QED’s first product line sold directly under its own brand was the RM52XX series—a cost-reduced derivative of the R5000 featuring smaller caches (16 KB on early RM52X0 models and 32 KB on later RM52X1 versions) with altered pin configurations. These included variants supporting both 32-bit (RM523X) and 64-bit (RM526X) system buses. This series achieved notable success in laser printer markets securing contracts with manufacturers like Hewlett-Packard, Lexmark, Ricoh, and Samsung.

The RM70XX series followed with enhancements including an on-chip level 2 cache of 256 KB—one of the earliest implementations in embedded processors—and symmetric superscalar execution with dual integer units. The RM7061 model provided pin compatibility upgrades over RM526X devices. This generation further strengthened QED’s position within embedded markets.

The RM9x00 family represented QED’s initial venture into System-on-a-Chip (SOC) technology. Its Apollo core featured an extended 7-stage pipeline enabling higher clock frequencies alongside dynamic branch prediction to mitigate latency penalties. The dual-core configuration reached operational speeds of up to 1 GHz. Integrated peripherals encompassed DDR memory controllers, SysAD bus controller, boot bus controller, DMA engines, and HyperTransport interfaces; subsequent revisions added Gigabit Ethernet, PCI controllers, and cache coherency mechanisms. Despite these technical advancements, delayed market entry combined with conservative staffing levels around QED’s IPO constrained commercial success. The sale to PMC-Sierra aimed to finance such SOC developments; however, competitors like SiByte had already introduced comparable products to market.

External links

Quantum Effect Devices/Design information at chipdb.org