Not to be confused with x86-64, the 64-bit extension to x86 architecture.IA-64 (also called Intel Itanium architecture) is the architecture of the Itanium family of 64-bit Intel microprocessors. The architecture originated at Hewlett-Packard (HP), and was later jointly developed by HP and Intel.The Itanium architecture is based on explicit instruction-level parallelism, in which the compiler decides which instructions to execute in parallel.