improve performance of uploading data to database

I have a c# application. When it runs it calculates about 50,000 to 100,000 values. I then store these values into a sql server database. The code below works fine however it takes a very long time to upload the data to the database. I would like to know if there is anything I can do to improve the performance? It currently take over a minute.

My Sql table shown below. Should I be using a primary key here as I imagine this must take extra processing time when inserting the data?

 tblResultEquityCurve

 DTime (smalldatetime) - primary key
 Equity numeric(18,4)

C# code

void exEquityCurveMT()
        {
            DeletePreviousResultsFromTable("Result_EquityCurve");

            Spliter[] split = MTSplitter(Account.EquityHistory.Count);
            MultiThreadToDataBase[] mtDB = new MultiThreadToDataBase[NUMCORES];

            Task[] taskDB = new Task[NUMCORES];
            for (int i = 0; i < taskDB.Length; i++)
            {
                List<structEquity> eqyList = Account.EquityHistory.GetRange((int)split[i].rowStart, split[i].numRows);
                mtDB[i] = new MultiThreadToDataBase();
                taskDB[i] = Task.Factory.StartNew(mtDB[i].exEquityCurve, eqyList);
            }
            try
            {
                Task.WaitAll(taskDB);
            }
            catch (AggregateException ex)
            {
                ExceptionDispatchInfo.Capture(ex.InnerException).Throw();
            }

        }




public void exEquityCurve(object dataObj)
        {
            List<structEquity> dataList = (List<structEquity>)dataObj;

            using (connection = new SqlConnection(connectionString))
            {
                connection.Open();

                using (SqlCommand commandEquity = new SqlCommand("dbo.InsertEquityCurve", connection))
                {
                    commandEquity.CommandType = System.Data.CommandType.StoredProcedure;
                    commandEquity.Parameters.Add("@dtTime", System.Data.SqlDbType.SmallDateTime);
                    commandEquity.Parameters.Add("@Equity", System.Data.SqlDbType.Float);

                    for (int i = 0; i < dataList.Count; i++)
                    {
                        commandEquity.Parameters["@dtTime"].Value = dataList[i].dTime;
                        commandEquity.Parameters["@Equity"].Value = dataList[i].Equity;
                        commandEquity.ExecuteNonQuery();
                    }                                
                }

                connection.Close();
            }
        }