ALT Question: How was AMD able to beat Intel in delivering the first x86-64 instruction set? Was Intel too distracted by the Itanium project? If so, why? Shouldn't Intel with its vast resources have been able to develop both architectures? Answer by Bob Colwell: Intel's Pentium 4 had our own internal version of x86-64. But you could not use it: we were forced to "fuse it off", meaning that even though the functionality was in there, it could not be exercised by a user. This was a marketing decision by Intel — they believed, probably rightly, that bringing out a new 64-bit feature in the x86 would be perceived as betting against their own native-64-bit Itanium, and might well severely damage Itanium's chances. I was told, not once, but twice, that if I "didn't stop yammering about the need to go 64-bits in x86 l'd be fired on the spot" and was directly ordered to take out that 64-bit stuff. I decided to split the difference, by leaving in the gates but fusing off the functionality…