Itanium - Wikipedia
Itanium 2

Intel shipped the Itanium 9700 today which is the last model that Intel intends to shop. HPE is the only vendor of the machines and the market for them is rather thin.

Itanium was incompatible with the desktop PC processor. This immediately make it unsuited for the consumer market.

Visual Studio 2005 is the only version known to support the CPU for code generation. Some earlier compilers for Alpha and MIPS are known from earlier servers.

Itanium launched in July 2001, and the latest version called Itanium 9700 “Kittson” has made its final destination on July 29th, when Intel decided to stop any further shipment of the Itanium generation. This marks an era where, currently, Intel is using only the x86-64 architecture in its server processors going forward.

AMD64 is a viable architecture and many such processors are seen in supercomputers. IBM PowerPC processors dominants the top 500 until Japan built a new machine.

It took several years for the AMD64 to be fine tuned enough to be efficient. Problems with Intel’s hyperthreading resulting in them redesigning their processors. AMD and Intel are both working on new DDR5 based systems and improved performance is expected.