title: What is the difference between x64 and IA-64?
body: <p>I was on Microsoft's website and noticed two different installers, one for x64 and one for IA-64. Reference:<a href="http://msdn.microsoft.com/en-us/library/5a4x27ek.aspx" rel="noreferrer">Installing the .NET Framework 4.5, 4.5.1</a></p>
  
  <p>My understanding is that IA-64 is a subclass of x64, so I'm curious why it would have a separate installer.</p>