Performance of Flash/AS3 vs. Silverlight/C#

A few months back, I posted some figures on the performance of Arrays, Vectors and linked lists in ActionScript 3.  Arrays were really slow, vectors much better, and linked lists the best, but all were slow compared to natively compiled C++ code.

Recently I’ve been experimenting with Silverlight and C#, and it generally seems much speedier than Flash and AS3. So I re-did the test I did a few months back, doing repeated element-by-element addition of two long arrays, this time using C#. I also redid the AS3 timing test, since I got a faster MacBook Pro since my last post on this subject. The core of the C# timing test code looks like this:

			int startTime = System.Environment.TickCount;
			for (int j = 0; j < LOOPS; j++)
			{
				for (int k = 0; k < N; k++)
				{
					z[k] = x[k] + y[k];
				}
			}
			int endTime = System.Environment.TickCount;

So here’s how Silverlight/C# stacks up against Flash/AS3:

Approach	Time (ms)
AS3, Array	713
AS3, Vector	408
AS3, Linked List	151
C#, Array	70

So for this simple test, C# arrays are over 5x faster than Vectors in AS3, and over double the speed of linked lists. This is only one test, of course, but if this sort of difference in performance is typical, it clearly has big implications on what’s possible on the two platforms. In particular, it makes Silverlight/C# very attractive for real-time audio applications, which require lots of array accessing and number crunching.  [Update 6 April 2011: I also found that an FFT I wrote ran ~4x faster in C# than in AS3. See An FFT in C#].

Tests were run on my MacBook Pro (2.66 GHz Intel Core i7, Mac OS 10.6.6), with Flash Player 10.1.52.14 and Silverlight 4.0.60129.0.

For the full C# timing test code, click “show code” below.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Diagnostics;

namespace SpeedTest
{
	public partial class MainPage : UserControl
	{
        private const int N = 5000;		// No. of elements in arrays
        private const int LOOPS = 5000;	// No. of times to repeat the calculations

		public MainPage()
		{
			InitializeComponent();

			int elapsed = ArrayTest();
			status.Content = "Elapsed: " + elapsed.ToString(); // Note: 'status' is a 'Label' defined in the project's xaml file.
		}

		/**
		 * Add elements of one array to elements of another
		 * array, and put the results into a third array.
		 */
		private int ArrayTest()
		{
			// Create arrays
			double[] x = new double[N];
			double[] y = new double[N];
			double[] z = new double[N];

			// Initialize them with some values
			for (int k = 0; k < N; k++)
			{
				x[k] = k;
				y[k] = k;
				z[k] = 0.0;
			}

			// Add the values in the two arrays, with result
			// in a third array.  Repeat many times.
			int startTime = System.Environment.TickCount;
			for (int j = 0; j < LOOPS; j++)
			{
				for (int k = 0; k < N; k++)
				{
					z[k] = x[k] + y[k];
				}
			}
			int endTime = System.Environment.TickCount;

			// Return the elapsed time.
			return (endTime - startTime);
		}
	}
}

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