title: What 64bit target to choose when compiling with Visual Studio (vcvarsall.bat)?
body: <p>The <code>vcvarsall.bat</code> that does setup de build environment let you choose between <code>x86 | ia64 | amd64 | x86_amd64 | x86_ia64</code>. </p>
  
  <p>First option is obvious for 32bit, but the question is: what would be the optimal option between the other 4 if you want to build for 64bit and you want to run on all 64 bit machines. </p>
  
  <p>Let say that you don't have time/resources to make 4 builds for 64 and you have to choose only one of them?</p>