for (int i=0;i<60000;i++)
{
var pr = new Record();
pr.Field1 = "sdsds"+i; // таких полей порядка 10-15
db.Records.InsertOnSunmit(pr);
}
db.SubmitChanges();

 public static class MyExtenders
    {
        public static DataTable ToDataTable<T>(this IEnumerable<T>
        collection)
        {
            DataTable dt = new DataTable();
            Type t = typeof(T);
            PropertyInfo[] pia = t.GetProperties().Where(x => IsAcceptableDbType(x)).ToArray();
            //Create the columns in the DataTable

            foreach (PropertyInfo pi in pia)
            {
                var attr = pi.Attributes;

                if (IsNullableType(pi.PropertyType))
                {
                    var nc = new NullableConverter(pi.PropertyType);
                    Type underlyingType = nc.UnderlyingType;
                    dt.Columns.Add(pi.Name, underlyingType);
                }
                else
                    dt.Columns.Add(pi.Name, pi.PropertyType);
            }
            //Populate the table
            foreach (T item in collection)
            {
                DataRow dr = dt.NewRow();
                dr.BeginEdit();
                foreach (PropertyInfo pi in pia)
                {
                    dr[pi.Name] = pi.GetValue(item, null) ?? DBNull.Value;
                }
                dr.EndEdit();
                dt.Rows.Add(dr);
            }
            return dt;
        }
        static bool IsAcceptableDbType(PropertyInfo pi)
        {
            return (pi.PropertyType.BaseType ==
                       Type.GetType("System.ValueType") ||
                       pi.PropertyType ==
                       Type.GetType("System.String"));
        }
        static bool IsNullableType(Type theType)
        {
            return (theType.IsGenericType && theType.
              GetGenericTypeDefinition().Equals
              (typeof(Nullable<>)));
        }
    }

  static bool IsAcceptableDbType(PropertyInfo pi)
        {
            return (pi.PropertyType.BaseType ==
                       Type.GetType("System.ValueType") ||
                       pi.PropertyType ==
                       Type.GetType("System.String"));
        }