What is the difference between x64 and IA-64?

Question

I was on Microsoft\'s website and noticed two different installers, one for x64 and one for IA-64. Reference:Installing the .NET Framework 4.5, 4.5.1

My understandin

Answer 1

IA-64 is for computers running Intel Itanium 64 bit processors. They do not support running 32 bit applications like x64 processors do. A special version of Windows is needed to run on these processors, thus the two different installers.