Is it faster to use regex to detect a browser's os, or indexOf?

check-navigator-platform-benchmark.js

//methodology: ran the test 4 times and took the slowest time.
 
checkOSRegex = function(){
  var os = navigator.platform;
  
  return /[wl]in/i.test(os) ? /win/i.test(os) ? 'linux' : 'windows' : 'mac'; //slightly confusing, but 26% faster than 
}
checkOSRegexStart = Date.now();
for(var i = 0; i < 1000000; i++){
  checkOSRegex('MacIntel');
  checkOSRegex('Linux i686');
  checkOSRegex('Win32');
  checkOSRegex('Commodore64');
}
chcekOSRegexTime = Date.now() - checkOSRegexStart; //7416 milliseconds
 
 
checkOSIndexOf = function(){
  var platform = navigator.platform.toUpperCase();
 
  if(platform.indexOf('MAC')!==-1)
    return 'mac';
  else if(platform.indexOf('WIN')!==-1)
    return 'win';
  return 'linux'
}
 
checkOSIndexOfStart = Date.now();
for(var i = 0; i < 1000000; i++){
  checkOSIndexOf('MacIntel');
  checkOSIndexOf('Linux i686');
  checkOSIndexOf('Win32');
  checkOSIndexOf('Commodore64');
}
chcekOSIndexOfTime = Date.now() - checkOSIndexOfStart; //9340 mi