<s>
In	O
integrated	O
circuits	O
,	O
the	O
stepping	B-General_Concept
level	I-General_Concept
or	O
revision	O
level	O
is	O
a	O
version	O
number	O
that	O
refers	O
to	O
the	O
introduction	O
or	O
revision	O
of	O
one	O
or	O
more	O
photolithographic	B-Algorithm
photomasks	B-Algorithm
within	O
the	O
set	O
of	O
photomasks	B-Algorithm
that	O
is	O
used	O
to	O
pattern	O
an	O
integrated	O
circuit	O
.	O
</s>
<s>
The	O
term	O
originated	O
from	O
the	O
name	O
of	O
the	O
equipment	O
(	O
"	B-Algorithm
steppers	I-Algorithm
"	I-Algorithm
)	O
that	O
exposes	O
the	O
photoresist	O
to	O
light	O
.	O
</s>
<s>
Integrated	O
circuits	O
have	O
two	O
primary	O
classes	O
of	O
mask	B-Algorithm
sets	I-Algorithm
:	O
firstly	O
,	O
"	O
base	O
"	O
layers	O
that	O
are	O
used	O
to	O
build	O
the	O
structures	O
,	O
such	O
as	O
transistors	O
,	O
that	O
comprise	O
circuit	O
logic	O
and	O
,	O
secondly	O
,	O
"	O
metal	O
"	O
layers	O
that	O
connect	O
the	O
circuit	O
logic	O
.	O
</s>
<s>
Typically	O
,	O
when	O
an	O
integrated	O
circuit	O
manufacturer	O
such	O
as	O
Intel	O
or	O
AMD	O
produces	O
a	O
new	O
stepping	B-General_Concept
(	O
i.e.	O
</s>
<s>
Many	O
integrated	O
circuits	O
allow	O
interrogation	O
to	O
reveal	O
information	O
about	O
their	O
features	O
,	O
including	O
stepping	B-General_Concept
level	I-General_Concept
.	O
</s>
<s>
For	O
example	O
,	O
executing	O
CPUID	B-Architecture
instruction	O
with	O
the	O
EAX	O
register	O
set	O
to	O
'	O
1	O
 '	O
on	O
x86	B-Operating_System
CPUs	O
will	O
result	O
in	O
values	O
being	O
placed	O
in	O
other	O
registers	O
that	O
show	O
the	O
CPU	O
's	O
stepping	B-General_Concept
level	I-General_Concept
.	O
</s>
<s>
Stepping	B-General_Concept
identifiers	O
commonly	O
comprise	O
a	O
letter	O
followed	O
by	O
a	O
number	O
,	O
for	O
example	O
B2	O
.	O
</s>
<s>
The	O
Intel	O
Core	O
microarchitecture	O
uses	O
a	O
number	O
of	O
steppings	B-General_Concept
,	O
which	O
unlike	O
prior	O
microarchitectures	O
not	O
only	O
represent	O
incremental	O
improvements	O
but	O
also	O
changes	O
to	O
features	O
,	O
such	O
as	O
a	O
different	O
cache	O
size	O
or	O
the	O
addition	O
of	O
low-power	O
modes	O
.	O
</s>
<s>
Most	O
of	O
these	O
steppings	B-General_Concept
are	O
used	O
across	O
brands	O
,	O
typically	O
involving	O
features	O
being	O
disabled	O
or	O
clock	O
frequencies	O
being	O
reduced	O
on	O
low-end	O
chips	O
.	O
</s>
<s>
Steppings	B-General_Concept
with	O
a	O
reduced	O
cache	O
size	O
use	O
a	O
separate	O
naming	O
scheme	O
,	O
which	O
means	O
that	O
CPU	O
steppings	B-General_Concept
are	O
not	O
necessarily	O
released	O
in	O
alphabetic	O
order	O
of	O
stepping	B-General_Concept
.	O
</s>
