What is "stepping"?

[speedy4500]

I see all kinds of codes concerning stepping like AXIA, AVIA, AHYJA, etc. that people say is the stepping and even the Intel 815EP with B-stepping for the tualatin. In WCPUID it says stepping and then two numbers such as 4 4 or 2 2. My question is this: what is stepping? how does it affect the chip?

[TranceBear]

Originally posted by Would71
Here's a starting point for ya:


That pic sure does look familiar