The Itanic Has Sunk
By today, July 29, 2021, Intel has shipped the last of its Itanium processors, the last holdout of a rough decade of their history. You'd be forgiven for not having heard of this unusual CPU as they carved a niche of a few supercomputers in the early 2000s and some legacy mainframe holdouts.
In 1994, Intel and HP looked around and saw a wide variety of successful server CPU architectures like Alpha, MIPS, SPARC, and POWER. This annoyed them and they decided to make a new CPU that no one would want to use. To these ends they invented an instruction set architecture that was impossible to program efficiently, planning that future compilers would be clever enough to make software run acceptably well. (This never happened because it turned out that anyone smart enough to write these compilers would rather be doing almost anything else.)
In 2000, Intel launched the NetBurst Pentium 4 CPU. It had serious design compromises that would hypothetically allow CPUs to run at upwards of 10GHz. Since these beasts could fry an egg at 3GHz, it was good that they never came anywhere near 10GHz as the heat would likely be sufficient to induce nearby hydrogen atoms to fuse.
Customers begged Intel to release a 64-bit Pentium-compatible CPU. They refused because they knew this would canibalize Itanium. Why write software for a weird and uncommon architecture if you could use something like the terrible x86 instruction set you already knew, but better?
In 2003, AMD launched their 64-bit, but Pentium-compatible, Opteron CPU. Everyone stopped buying Intel CPUs for a while. Within a few years Intel made their own 64-bit, but AMD-compatible, CPUs to avoid entirely losing the desktop and small server market. They were right earlier: almost everyone immediately embraced AMD's instruction set and no one but HP wanted anything to do with Itanium.
And then, for a long time, nothing much happened. That's happy news when you're talking about earthquakes or tornados, but not so hot when you're talking about sales of processors you spent a few billion dollars developing.
In 2015, HP admitted defeat and launched a line of mainframes using AMD's 64-bit instruction set so developers could write and test software on systems that cost both over and under a million dollars.
Intel was contractually obligated to keep Itanium limping along but it was apparent their heart wasn't in it. In 2019 they accepted the inevitable and announced that Itanium would be officially dead as of today. The final batch of CPUs was built on a 32nm process when everyone else was on to 10nm, 7nm, and 5nm designs.
Goodbye, Itanic. You were a strange, unloved little detour, better known for the good designs you killed than for any successes of your own. Few will miss you.
Ironically, in 2020 Apple launched their own desktop-class CPU that wasn't compatible with more common Intel or AMD designs. The difference was that Apple's M1 was actually nice and fast, both for developers and end users.