NPOI read big files

Jan 13 at 4:28 PM
i m trying to use NPOI dll to import excel files, but with very large documents(more 56mb and 65k rows/250 columns) it s too low.
is there any method to open the excel without the preload?

now i open excel with this code
HSSFWorkbook hssfwb;
using (FileStream file = new FileStream(@"\\\tmp\test.xls", FileMode.Open, FileAccess.Read))
      //here the problem!!!
      hssfwb = new HSSFWorkbook(file,false);
before i used that open the file like a text(with filestream) and i loop data like a normal text.
(i dismissed it because i had some problems on encoding).
this is what i done before and what i hope to do with NPOI.
private void read()
            FileStream stream = File.Open(@"\\\tmp\test.xls", FileMode.Open, FileAccess.Read);
            IExcelDataReader excelReader = ExcelReaderFactory.CreateBinaryReader(stream);

            while (excelReader.Read())

            DataSet result = excelReader.AsDataSet();
is there any possibilities?

thank you