Intel could have beaten AMD to 64-bit transition but wrongly chose not to, engineers reveal

Intel had a hidden x86-64 instruction set embedded in Pentium 4 chips, but management forced engineers to disable it. The company focused on Itanium instead, believing a 64-bit Pentium 4 would hurt Itanium's market chances. This decision backfired when AMD successfully introduced x86-64, forcing Intel to quickly implement its own version. The x86-64 architecture, which maintained compatibility with older x86 software while adding 64-bit capabilities, eventually became the standard for PC processors.