Performance application x64 vs x86

string[] arrayPosicionOrden = new string[1181];


           arrayPosicionOrden[0] =(char)(miOrden._Side.Length+32) + (miOrden._Side);
           arrayPosicionOrden[1] = (char)(miOrden._Quantity.Length + 32) + (miOrden._Quantity);
           arrayPosicionOrden[2] = (char)(miOrden._Modality.Length + 32) + (miOrden._Modality);
           arrayPosicionOrden[3] = (char)(miOrden._Price.Length + 32) + (miOrden._Price);
           arrayPosicionOrden[4] = (char)(miOrden._Validity.Length + 32) + (miOrden._Validity);
           arrayPosicionOrden[5] = (char)(miOrden._ExpiryDate.Length + 32) + (miOrden._ExpiryDate);
           arrayPosicionOrden[8] = (char)(miOrden._MinimumQuantity.Length + 32) + (miOrden._MinimumQuantity);
           arrayPosicionOrden[9] = (char)(miOrden._DisplayedQuantity.Length + 32) + (miOrden._DisplayedQuantity);
           arrayPosicionOrden[10] = (char)(miOrden._ClientReference1.Length + 32) + (miOrden._ClientReference1);
           arrayPosicionOrden[12] = (char)(miOrden._internalReference.Length + 32) + (miOrden._internalReference);
           arrayPosicionOrden[13] = (char)(miOrden._ExchangeNumber.Length + 32) + (miOrden._ExchangeNumber);
           arrayPosicionOrden[16] = (char)(miOrden._OrderType.Length + 32) + (miOrden._OrderType);
           arrayPosicionOrden[17] = (char)(miOrden._TypeOfCustomerAccount.Length + 32) + (miOrden._TypeOfCustomerAccount);
           arrayPosicionOrden[20] = (char)(miOrden._AllocatedMember2.Length + 32) + (miOrden._AllocatedMember2);
           arrayPosicionOrden[81] = (char)(miOrden._Memo.Length + 32) + (miOrden._Memo);
           arrayPosicionOrden[106] = (char)(miOrden._GLID.Length + 32) + (miOrden._GLID);
           arrayPosicionOrden[196] = (char)(miOrden._TriggeringParameter.Length + 32) + (miOrden._TriggeringParameter);
           arrayPosicionOrden[209] = (char)(miOrden._ValidityType.Length + 32) + (miOrden._ValidityType);