Itanium
A 64-bit Intel architecture that failed to supplant x86.
Itanium was a line of 64-bit microprocessors from Intel, built around the Intel Itanium architecture, previously known as IA-64. The architecture was first developed at Hewlett-Packard and later became a joint project between HP and Intel. When the processors launched in June 2001, Intel aimed them at enterprise servers and high-performance computing. During the design phase, engineers boasted that the architecture could outperform PowerPC and even eliminate x86. Early forecasts predicted IA-64 would move into lower-end servers, replace Xeon, and eventually enter personal computers, ultimately overtaking both RISC and CISC architectures for all general-purpose tasks.
After a decade of development, the first Itanium chips arrived in 2001, but their performance fell short compared to established RISC and CISC processors. Emulation for running existing x86 software and operating systems was especially weak. HP and its successor, Hewlett Packard Enterprise, produced Itanium-based systems under the Integrity Servers line, along with several other manufacturers. By 2008, Itanium ranked as the fourth most widely used microprocessor architecture for enterprise systems, trailing x86-64, Power ISA, and SPARC.
Intel released the final generation, codenamed Kittson, to test customers in February 2017, with volume shipments starting that May. These chips were used only in mission-critical servers from HPE. In 2019, Intel announced it would accept new orders for Itanium until January 30, 2020, and stop shipments by July 29, 2021, a timeline that was followed.
Itanium never achieved broad sales beyond enterprise servers and high-performance computing. The architecture was eventually overtaken by AMD’s x86-64, also known as AMD64, an extension of the 32-bit x86 architecture used in Intel’s Xeon and AMD’s Opteron lines. By 2009, most servers shipped with x86-64 processors, which also dominated the low-cost desktop and laptop markets that Itanium had not targeted. Techspot declared the architecture dead in an article titled "Intel's Itanium is finally dead: The Itanic sunken by the x86 juggernaut," noting that Itanium’s promise was sunk by a lack of legacy 32-bit support and difficulties in writing and maintaining software for its architecture, while the dream of a single dominant ISA was realized by AMD64 extensions.
Quick Facts
- Produced-Start
- Itanium was launched on 29 May, but the computers containing it shipped to customers in June.
- Produced-End
- 2020-01-30
- Slowest
- 733
- Slow-Unit
- MHz
- Fastest
- 2.66
- Fast-Unit
- GHz
- Fsb-Slowest
- 266
- Fsb-Slow-Unit
- MT/s
- Fsb-Fastest
- 667
- Arch
- IA-64
- Numcores
- 1, 2, 4 or 8
Facts from the source article.
Lore & Background
The Itanium architecture originated from HP's research into an architecture that would exceed the expected limits of RISC architectures, driven by the increasing complexity of executing multiple instructions per cycle. HP hired pioneers of VLIW computing and modified classic VLIW into a new type called Explicitly Parallel Instruction Computing (EPIC), which used template bits to show instruction independence, predication to reduce branches, and full interlocking to eliminate delay slots. In 1993, HP held an internal competition where an EPIC team won with over double the simulated performance of a RISC competitor. Intel, meanwhile, had been looking for ways to make better ISAs and had launched the i860 in 1989, which failed partly because compilers did not support its parallel features. In November 1993, HP approached Intel seeking collaboration. Intel's engineers were impressed by HP's PA-WideWord architecture, and in 1994 Intel canceled its existing plans for a 64-bit x86 extension codenamed P7. The joint effort was announced in June 1994. The first product, Merced, was designed by a team of 500, which Intel later admitted was too inexperienced, with many recent college graduates. Early in development, HP and Intel disagreed over floating-point hardware; HP prevailed after the discovery of a floating-point hardware bug in Intel's Pentium.
Reader's Guide
When first released in 2001 after a decade of development, Itanium's performance was disappointing compared to better-established RISC and CISC processors. Emulation to run existing x86 applications and operating systems was particularly poor. Itanium-based systems were produced by HP and its successor Hewlett Packard Enterprise as the Integrity Servers line, and by several other manufacturers. In 2008, Itanium was the fourth-most deployed microprocessor architecture for enterprise-class systems, behind x86-64, Power ISA, and SPARC. It never sold well outside enterprise servers and high-performance computing systems, and the architecture was ultimately supplanted by competitor AMD's x86-64 (also called AMD64) architecture, a compatible extension to 32-bit x86 implemented by Intel's Xeon line and AMD's Opteron line. By 2009, most servers were being shipped with x86-64 processors, which also dominate the low-cost desktop and laptop markets not initially targeted by Itanium. The final generation, Kittson, was released in 2017 and used only in mission-critical servers from HPE. Intel announced in 2019 that new orders would be accepted until January 30, 2020, and shipments would cease by July 29, 2021, which took place on schedule. The architecture's promise was sunk by a lack of legacy 32-bit support and difficulties in working with the architecture for writing and maintaining software, while the dream of a single dominant ISA was realized by the AMD64 extensions.
Did You Know?
- The Itanium architecture originated at HP and was later jointly developed by HP and Intel.
- Early predictions were that IA-64 would eventually supplant RISC and CISC architectures for all general-purpose applications.
- The final Itanium generation, Kittson, was only used in mission-critical servers from HPE.
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