ActionScript 3 Vector / Array Performance Comparison at Mike

In my original post on the new Flash Player 10 Vector class, I did a simple example that showed Vectors being slightly faster than Array when just populating and looping through collections.
Below is another example that shows a more significant performance increase when using Vectors. In this example, I populate an Array and Vector with 5 million random numbers, and then loop through them and average all of the numbers.

Running the test on my MacBook Pro, the Vector is about 60% faster:
Vector 1.824
Array 2.938
62.08 %
Here is the code:

package {
 import flash.display.Sprite;
 import __AS3__.vec.Vector;

 public class VectorPerformance extends Sprite
 {
  private static const LENGTH:int = 5000000;

  public function VectorPerformance()
  {
   //vector performance
   var vectorStartTime:Number = getTime();

   var v:Vector.<Number> = generateVector();
   var vAvg:Number = averageVector(v);

   var vectorTime:Number = (getTime() - vectorStartTime) / 1000;

   //array performance
   var arrayStartTime:Number = getTime();

   var a:Array = generateArray();
   var aAvg:Number = averageArray(a);

   var arrayTime:Number = (getTime() - arrayStartTime) / 1000;

   trace("Vector", vectorTime);
   trace("Array", arrayTime);
   trace((vectorTime/arrayTime) * 100 + " %");
  }

  private function generateVector():Vector.<Number>
  {
   var v:Vector.<Number> = new Vector.<Number>(LENGTH, true);

   for(var i:int = 0; i < LENGTH; i++)
   {
    v[i] = Math.random() * 100000;
   }

   return v;
  }

  private function averageVector(v:Vector.<Number>):Number
  {
   var sum:Number = 0;
   var len:int = v.length;

   for(var i:int = 0; i < LENGTH; i++)
   {
    sum += v[i];
   }

   return (sum / len);
  }

  private function generateArray():Array
  {
   var a:Array = new Array(LENGTH);

   for(var i:int = 0; i < LENGTH; i++)
   {
    a[i] = Math.random() * 100000;
   }

   return a;
  }

  private function averageArray(arr:Array):Number
  {
   var sum:Number = 0;
   var len:int = arr.length;

   for(var i:int = 0; i < LENGTH; i++)
   {
    sum += arr[i];
   }

   return (sum / len);
  }  

  private function getTime():Number
  {
   return (new Date()).getTime();
  }
 }
}