title: Is float slower than double? Does 64 bit program run faster than 32 bit program?
body: <p>Is using <code>float</code> type slower than using <code>double</code> type?</p>
  
  <p>I heard that modern Intel and AMD CPUs can do calculations with doubles faster than with floats.</p>
  
  <p>What about standard math functions (<code>sqrt</code>, <code>pow</code>, <code>log</code>, <code>sin</code>, <code>cos</code>, etc.)? Computing them in single-precision should be considerably faster because it should require less floating-point operations. For example, single precision <code>sqrt</code> can use simpler math formula than double precision <code>sqrt</code>. Also, I heard that standard math functions are faster in 64 bit mode (when compiled and run on 64 bit OS). What is the definitive answer on this?</p>