There is more than one type of stepping regarding CPU's.. But i believe your talking of the two letter stepping revision number for All processors. A new processor starts with a revision stepping of A-0. As small problems are found and fixed the stepping number changes, A-1, A-2, and so on. If a big problem is corrected they will change the letter, A-2 to B-0 for example. The revision stepping is simply an indication of Whats been done to the CPU. So it wont restrict your ability to use it as long as your motherboard supports the chip.