プロファイル（for vs foreach)

C#を使用しているとC言語だとforで記述している部分を(foreach)でも表記できる場合がおおいのですが、どっちがはやいのかな？

namespace Profiler2
{
    public class Game1 : Microsoft.Xna.Framework.Game
    {
        GraphicsDeviceManager graphics;
        SpriteBatch spriteBatch;
        private SpriteFont font;
        private TimeSpan timeData;

        const int V_MAX = 100;
        private Vector2[] vTest = new Vector2[V_MAX];

        public Game1()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";
            graphics.PreferredBackBufferWidth = 240;
            graphics.PreferredBackBufferHeight = 320;
            // Frame rate is 30 fps by default for Zune.
            TargetElapsedTime = TimeSpan.FromSeconds(1 / 30.0);
        }

        protected override void LoadContent()
        {
            spriteBatch = new SpriteBatch(GraphicsDevice);
            font = Content.Load<SpriteFont>("SpriteFont1");
            for (int i = 0; i < V_MAX; i++)
                vTest[i] = new Vector2();
        }

        protected override void Update(GameTime gameTime)
        {
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
                this.Exit();
            base.Update(gameTime);
        }

        protected override void Draw(GameTime gameTime)
        {
            DateTime timeNow = DateTime.Now;
            for (int i = 0; i < 1000000; i++)
                forTest2();
            timeData = DateTime.Now - timeNow;
            //----------------------------
            GraphicsDevice.Clear(Color.CornflowerBlue);
            spriteBatch.Begin();
            spriteBatch.DrawString(font, "time:" + timeData.TotalMilliseconds, new Vector2(50, 50), Color.White);
            spriteBatch.End();
            base.Draw(gameTime);
        }

        private void forTest()
        {
            float   f;
            for (int i = 0; i < V_MAX; i++)
                f = vTest[i].X;
        }
    }
}

■forに関して

        private void forTest()
        {
            float   f;
            for (int i = 0; i < V_MAX; i++)
                f = vTest[i].X;
        }

.method private hidebysig instance void  forTest() cil managed
{
  // コード サイズ       32 (0x20)
  .maxstack  2
  .locals init ([0] int32 i)
  IL_0000:  ldc.i4.0
  IL_0001:  stloc.0
  IL_0002:  br.s       IL_001a
  IL_0004:  ldarg.0
  IL_0005:  ldfld      valuetype [Microsoft.Xna.Framework]Microsoft.Xna.Framework.Vector2[] Profiler2.Game1::vTest
  IL_000a:  ldloc.0
  IL_000b:  ldelema    [Microsoft.Xna.Framework]Microsoft.Xna.Framework.Vector2
  IL_0010:  ldfld      float32 [Microsoft.Xna.Framework]Microsoft.Xna.Framework.Vector2::X
  IL_0015:  pop
  IL_0016:  ldloc.0
  IL_0017:  ldc.i4.1
  IL_0018:  add
  IL_0019:  stloc.0
  IL_001a:  ldloc.0
  IL_001b:  ldc.i4.s   100
  IL_001d:  blt.s      IL_0004
  IL_001f:  ret
} // end of method Game1::forTest

■foreachに関して

        private void forTest()
        {
            float f;
            foreach (Vector2 v in vTest)
                f = v.X;
        }

.method private hidebysig instance void  forTest() cil managed
{
  // コード サイズ       35 (0x23)
  .maxstack  2
  .locals init ([0] valuetype [Microsoft.Xna.Framework]Microsoft.Xna.Framework.Vector2 v,
           [1] valuetype [Microsoft.Xna.Framework]Microsoft.Xna.Framework.Vector2[] CS$6$0000,
           [2] int32 CS$7$0001)
  IL_0000:  ldarg.0
  IL_0001:  ldfld      valuetype [Microsoft.Xna.Framework]Microsoft.Xna.Framework.Vector2[] Profiler2.Game1::vTest
  IL_0006:  stloc.1
  IL_0007:  ldc.i4.0
  IL_0008:  stloc.2
  IL_0009:  br.s       IL_001c
  IL_000b:  ldloc.1
  IL_000c:  ldloc.2
  IL_000d:  ldelema    [Microsoft.Xna.Framework]Microsoft.Xna.Framework.Vector2
  IL_0012:  ldobj      [Microsoft.Xna.Framework]Microsoft.Xna.Framework.Vector2
  IL_0017:  stloc.0
  IL_0018:  ldloc.2
  IL_0019:  ldc.i4.1
  IL_001a:  add
  IL_001b:  stloc.2
  IL_001c:  ldloc.2
  IL_001d:  ldloc.1
  IL_001e:  ldlen
  IL_001f:  conv.i4
  IL_0020:  blt.s      IL_000b
  IL_0022:  ret
} // end of method Game1::forTest

■比較
・forの場合
　453.128ms(debug)
　93.75ms(Release)
・foreachの場合
　562.5ms(debug)
　78.125ms(Release)
デバッグだと for の方が早かったのですが、Releaseだと　foreach の方が早い結果が得られました。
なるべく　foreach にした方がループの部分はいいみたい。