If you do not use DFT(REORDER) and either OPTIMIZE(2) or OPTIMIZE(3), you will not get good performance from the compiler generated code.
Also, do not use OPT(2) or OPT(3) without DFT(REORDER) - the compiler will generate worse code and take much longer to do so.
Note that OPT(3) will produce slightly better code than OPT(2), but the compiler will take much longer to compiler programs (especially large programs) under OPT(3) than under OPT(2). For this reason, the compiler maps OPT(TIME) to OPT(2).