cropping an area from BitmapData with C#

I have a bitmap sourceImage.bmp

locking it's bits:

BitmapData dataOriginal = sourceImage.LockBits(new Rectangle(0, 0, sourceImage.Width, sourceImage.Height), ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);

Do analysis, get a clone:

Bitmap originalClone = AForge.Imaging.Image.Clone(dataOriginal);

unlocking bits:

sourceImage.UnlockBits(dataOriginal);

is it possible to specify which part of "dataOriginal" to copy (x,y,w,h)? or to create new data from the dataOriginal, specifying X and Y coordinates as well as H and W?

The aim is to copy a small area from this image. This method might be faster than DrawImage, that's why I don't use the latter.

Edit:

So I took 29 Mb bitmap and did some hardcore testing! Full-size crop (basically a copy) + 100 iterations.

Code:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using AForge;
using AForge.Imaging;
using System.Diagnostics;
using System.Drawing.Imaging;
using System.IO;
using System.Runtime.InteropServices;


namespace testCropClone
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private unsafe Bitmap Clone(Bitmap bmp, int startX, int startY, int width, int height)
        {
        Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height);
        BitmapData rawOriginal = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);

        int origByteCount = rawOriginal.Stride * rawOriginal.Height;
        byte[]