[2.0] Help speeding up pixel color code [resolved]

[cx323]

public static string OIR(string strPicPath)
        {
            int y = 0;
            int x = 0;

            DateTime tmStart = DateTime.Now;
            
            Bitmap b = new Bitmap(strPicPath);
            BitmapData bmData = b.LockBits(new Rectangle(0, 0, b.Width, b.Height),
            ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
            int stride = bmData.Stride;
            System.IntPtr Scan0 = bmData.Scan0;
            unsafe
            {
                byte* p = (byte*)(void*)Scan0;

                int nOffset = stride - b.Width * 3;

                byte red, green, blue;

                for (y = 0; y < b.Height; y++)
                {
                    for (x = 0; x < b.Width; x++)
                    {
                        blue = p[0];
                        green = p[1];
                        red = p[2];

                        if (blue < 40 && green < 90 && red < 80)
                        {
                            DateTime tmEnd = DateTime.Now;
                            TimeSpan tmDiff = tmEnd - tmStart;
                            //MessageBox.Show ("blue: " + blue + "green: " + "red: " + red);
                            MessageBox.Show("x: " + x + "y: " + y);
                            MessageBox.Show(tmDiff.TotalMilliseconds.ToString());
                            return "&x=" + x + "&y=" + y;
                        }

                        p += 3;
                    }
                    p += nOffset;
                }
            }
            return "&x=" + x + "&y=" + y;
        }

The code above is a function to find the x and y coordinates of a dark pixel. It works fine, but it's really slow, it take around 150ms on a 220x180 pixel image. In vb6 i was able to use dma and it took less than a ms, so i assume there's a better way. If someone could tell me what way would be faster that would be great. Thanks