Creating a Huge Dummy File in a Matter of Seconds in C#

I want to create a huge dummy file say 1~2 GBs in matter of seconds. here is what I've written in C#:

file.writeallbytes("filename",new byte[a huge number]);

and another way with indicating the status, was like following:

long FSS = din.TotalFreeSpace;
long segments = FSS / 10000;
long last_seg = FSS % 10000;
BinaryWriter br = new BinaryWriter(fs);

for (long i = 0; i < segments; i++)
{
    br.Write(new byte[10000]);

    this.label2.Text = "segments write :" + i.ToString() + "\r\n" + "segments remain :" + ((segments-i)+1).ToString();
    Application.DoEvents();
}
br.Write(new byte[last_seg]);
this.label2.Text += "\r\nDone!";
br.Close();

where din is Disk Information object

well with these two approach it takes something like 2 or more minutes to write such a big but dummy file. Is there any other faster way for doing so?