The saga of the evolution of the 64-bit instruction set of x86 CPU lineage is a fascinating one. Intel initially delved into the realm of new architecture with IA-64 in the Itanium CPU, which ultimately succumbed to the superiority of AMD64, an extension of the original 32-bit instruction set. Eventually, Intel had to acquire rights to AMD64, rebranding it as x86-64.
However, this narrative may need a revision as Bob Colwell, the former head of Intel’s x86 architecture team during the Pentium 4 era, revealed on Quora that the Pentium 4 did possess its own x86-64 instruction set, albeit disabled. This decision was influenced by Intel’s management at the time, prioritizing the Itanium over Pentium 4.
Colwell explained that Intel’s choice to disable x86-64 on the Pentium 4 was purely market-driven, as the company feared direct competition with the Itanium’s IA-64 architecture, jeopardizing its push for Itanium dominance. He further mentioned receiving directives from Intel’s management to refrain from advocating the significance of advancing x86 to 64-bit, under the threat of termination.
In a Quora thread where Colwell participated, a question was raised about how AMD managed to outperform Intel in introducing x86-64 CPUs, despite Intel’s vast resources. The answer to this seems clear now.
TLDR: The evolution of x86 CPU architecture, the rivalry between IA-64 and x86-64, and the strategic decisions made by Intel during the Pentium 4 era shed light on the intricate dynamics of the processor industry.
Leave a Comment