Is datareader quicker than dataset when populating a datatable?

Question

Which would be quicker.

1) Looping a datareader and creating a custom rows and columns based populated datatable

2) Or creating a dataAdapter object and just

Answer 1

Your option #1 would be slower. However, there's a better way to convert a datareader to a datatable than adding custom rows by hand:

DataTable dt = new DataTable();

using (SqlConnection conn = GetOpenSqlConnection())
using (SqlCommand cmd = new SqlCommand("SQL Query here", conn)
using (IDataReader rdr = cmd.ExecuteReader())
{
    dt.Load(rdr);
}

I can't comment on the difference between this and using .Fill().