What is quicker Code or Procedure

Hello, Could somebody tell what (and why) is faster the code below or the stored procedure. I'm trying to figure out what code I should place in stored procedures and what to use C# for.

/// <summary>
/// Generates barcode from DB
/// </summary>
/// <param name="nSupplierID"></param>
/// <param name="nItemIndex">The 1 based index of item in the products table</param>
/// <returns></returns>
private string GenerateBarcode(int nSupplierID, int nItemIndex)
{
//First get the supplier code
string strSQL = "SELECT Supplier_Code FROM tblSuppliers WHERE Supplier_ID = " + nSupplierID.ToString();
                  
this.m_sqlCommand.CommandText = strSQL;
string strSupplierCode = (string)m_sqlCommand.ExecuteScalar();
                                    
//Build the barcode form i.e. Month+Year+SupplierCode
string strBarcodeForm = DateTime.Now.ToString("MMyy") +  strSupplierCode;
                  
//Find the MAX barcode of this format in the DB, eg. SELECT MAX(BarCode) FROM tblProducts WHERE BarCode LIKE '0804PAM%'
strSQL = "SELECT MAX(BarCode) FROM tblProducts WHERE BarCode LIKE '" + strBarcodeForm + "%'";
                  
string strBarcode = "";

try
{
this.m_sqlCommand.CommandText = strSQL;
strBarcode = (string)m_sqlCommand.ExecuteScalar();
}
catch(InvalidCastException ex)
{
//If no value for the perticular barcode format exist in DB an InvalidCastException occurs
Debug.WriteLine("GenetrateBarcode() - " + ex.ToString());
strBarcode = strBarcodeForm + "00001";
return strBarcode;
}

//If a barode of that format exists we must increment and return it
int strBarcodeIndex = Convert.ToInt32(strBarcode.Substring(strBarcode.Length - 5, 5));
strBarcodeIndex += nItemIndex;
                  
//2) Create Barcode
strBarcode = strBarcodeForm + strBarcodeIndex.ToString("00000");
return strBarcode;
}

Or the below stored procedure

ALTER PROCEDURE dbo.GenerateBarcode
(
      @pSupplierID int,
      @pBarcode VARCHAR(20) OUTPUT,
      @pProductIndex int
)
AS
DECLARE @BarcodeDate DATETIME
SET @BarcodeDate = GETDATE()

DECLARE @BarcodeIndex NVARCHAR(10)
--Construct Date Part
SET @BarcodeIndex = STUFF('00', 2-len(MONTH(GETDATE()))+1, 2, MONTH(GETDATE())) + right(CONVERT(nvarchar, YEAR(GETDATE())), 2)

--Add Supplier Code
SELECT @BarcodeIndex = @BarcodeIndex + (SELECT Supplier_Code FROM tblSuppliers WHERE Supplier_ID = @pSupplierID)

--Get the highest value of this type of barcode
SELECT @pBarcode = MAX(BarCode) FROM tblProducts WHERE BarCode LIKE (@BarcodeIndex + '%')

--Increment Barcode
DECLARE @nNewIndex int
--Parse last 5 chars from Barcode (e.g. 0804JOM"000020")
SET @nNewIndex = CONVERT(int, SUBSTRING( @pBarcode, LEN(@pBarcode) - 4, 5)) + @pProductIndex
SET @pBarcode = @BarcodeIndex + RIGHT('00000' + CAST(@nNewIndex AS VARCHAR(5)), 5)


      RETURN