<s>
PowerPC	B-General_Concept
G4	I-General_Concept
is	O
a	O
designation	O
formerly	O
used	O
by	O
Apple	O
and	O
Eyetech	O
to	O
describe	O
a	O
fourth	O
generation	O
of	O
32-bit	O
PowerPC	B-Architecture
microprocessors	B-Architecture
.	O
</s>
<s>
Motorola	O
and	O
Freescale	O
's	O
proper	O
name	O
of	O
this	O
family	O
of	O
processors	O
is	O
PowerPC	B-General_Concept
74xx	I-General_Concept
.	O
</s>
<s>
Macintosh	B-Device
computers	O
such	O
as	O
the	O
PowerBook	B-Operating_System
G4	I-Operating_System
and	O
iBook	B-Device
G4	I-Device
laptops	O
and	O
the	O
Power	B-Device
Mac	I-Device
G4	I-Device
and	O
Power	B-Device
Mac	I-Device
G4	I-Device
Cube	I-Device
desktops	O
all	O
took	O
their	O
name	O
from	O
the	O
processor	O
.	O
</s>
<s>
PowerPC	B-General_Concept
G4	I-General_Concept
processors	O
were	O
also	O
used	O
in	O
the	O
eMac	B-Device
,	O
first-generation	O
Xserves	B-Device
,	O
first-generation	O
Mac	B-Device
Minis	I-Device
,	O
and	O
the	O
iMac	B-Device
G4	I-Device
before	O
the	O
introduction	O
of	O
the	O
PowerPC	B-General_Concept
970	I-General_Concept
.	O
</s>
<s>
Apple	O
completely	O
phased	O
out	O
the	O
G4	O
series	O
for	O
desktop	O
models	O
after	O
it	O
selected	O
the	O
64-bit	O
IBM-produced	O
PowerPC	B-General_Concept
970	I-General_Concept
processor	O
as	O
the	O
basis	O
for	O
its	O
PowerPC	B-General_Concept
G5	I-General_Concept
series	O
.	O
</s>
<s>
The	O
last	O
desktop	O
model	O
that	O
used	O
the	O
G4	O
was	O
the	O
Mac	B-Device
Mini	I-Device
which	O
now	O
comes	O
with	O
an	O
Apple	B-Device
M1	I-Device
processor	O
.	O
</s>
<s>
The	O
last	O
portable	O
to	O
use	O
the	O
G4	O
was	O
the	O
iBook	B-Device
G4	I-Device
but	O
was	O
replaced	O
by	O
the	O
Intel-based	O
MacBook	B-Device
.	O
</s>
<s>
The	O
PowerBook	B-Operating_System
G4	I-Operating_System
has	O
been	O
replaced	O
by	O
the	O
Intel-based	O
MacBook	B-Device
Pro	I-Device
.	O
</s>
<s>
The	O
PowerPC	B-General_Concept
G4	I-General_Concept
processors	O
are	O
also	O
popular	O
in	O
other	O
computer	O
systems	O
,	O
such	O
as	O
the	O
AmigaOne	B-Device
series	O
of	O
computers	O
and	O
the	O
Pegasos	B-Device
from	O
Genesi	O
.	O
</s>
<s>
Besides	O
desktop	O
computers	O
the	O
PowerPC	B-General_Concept
G4	I-General_Concept
is	O
popular	O
in	O
embedded	O
environments	O
,	O
like	O
routers	O
,	O
telecom	O
switches	O
,	O
imaging	O
,	O
media	O
processing	O
,	O
avionics	O
and	O
military	O
applications	O
,	O
where	O
one	O
can	O
take	O
advantage	O
of	O
the	O
AltiVec	B-General_Concept
and	O
its	O
SMP	B-Operating_System
capabilities	O
.	O
</s>
<s>
The	O
PowerPC	B-Architecture
7400	O
(	O
code-named	O
"	O
Max	O
"	O
)	O
debuted	O
in	O
August	O
1999	O
and	O
was	O
the	O
first	O
processor	O
to	O
carry	O
the	O
"	O
G4	O
"	O
moniker	O
.	O
</s>
<s>
This	O
forced	O
Apple	O
to	O
take	O
back	O
the	O
advertised	O
500MHz	O
models	O
of	O
Power	B-Device
Mac	I-Device
G4	I-Device
.	O
</s>
<s>
Ultimately	O
,	O
the	O
G4	O
architecture	O
design	O
contained	O
a	O
128-bit	O
vector	O
processing	O
unit	O
labelled	O
AltiVec	B-General_Concept
by	O
Motorola	O
while	O
Apple	O
marketing	O
referred	O
to	O
it	O
as	O
the	O
"	O
Velocity	B-General_Concept
Engine	I-General_Concept
"	O
.	O
</s>
<s>
The	O
PowerPC	B-General_Concept
970	I-General_Concept
(	O
G5	O
)	O
was	O
the	O
first	O
IBM-manufactured	O
CPU	O
to	O
implement	O
VMX/AltiVec	B-General_Concept
,	O
for	O
which	O
IBM	O
reused	O
the	O
old	O
7400	O
design	O
they	O
still	O
had	O
from	O
the	O
design	O
they	O
did	O
with	O
Motorola	O
in	O
Somerset	O
.	O
</s>
<s>
The	O
Xenon	B-Device
CPU	I-Device
in	O
the	B-Operating_System
Xbox	I-Operating_System
360	I-Operating_System
also	O
features	O
VMX	O
,	O
with	O
added	O
proprietary	O
extensions	O
made	O
especially	O
for	O
Microsoft	O
.	O
</s>
<s>
POWER6	B-Device
,	O
introduced	O
in	O
2007	O
,	O
is	O
IBMs	O
first	O
"	O
big	B-Architecture
iron	I-Architecture
"	O
CPU	O
to	O
also	O
implement	O
VMX	O
.	O
</s>
<s>
With	O
the	O
AltiVec	B-General_Concept
unit	O
,	O
the	O
7400	O
microprocessor	B-Architecture
can	O
do	O
four-way	O
single	O
precision	O
(	O
32-bit	O
)	O
floating	B-Algorithm
point	I-Algorithm
math	I-Algorithm
,	O
or	O
16-way	O
8-bit	O
,	O
8-way	O
16-bit	O
or	O
four-way	O
32-bit	O
integer	O
math	O
in	O
a	O
single	O
cycle	O
.	O
</s>
<s>
Furthermore	O
,	O
the	O
vector	O
processing	O
unit	O
is	O
superscalar	B-General_Concept
,	O
and	O
can	O
do	O
two	O
vector	O
operations	O
at	O
the	O
same	O
time	O
.	O
</s>
<s>
Compared	O
to	O
Intel	O
's	O
x86	B-Operating_System
microprocessors	I-Operating_System
at	O
the	O
time	O
,	O
this	O
feature	O
offered	O
a	O
substantial	O
performance	O
boost	O
to	O
applications	O
designed	O
to	O
take	O
advantage	O
of	O
the	O
AltiVec	B-General_Concept
unit	O
.	O
</s>
<s>
Some	O
examples	O
are	O
Adobe	O
Photoshop	O
which	O
utilises	O
the	O
AltiVec	B-General_Concept
unit	O
for	O
faster	O
rendering	O
of	O
effects	O
and	O
transitions	O
,	O
and	O
Apple	O
's	O
iLife	B-Application
suite	O
which	O
takes	O
advantage	O
of	O
the	O
unit	O
for	O
importing	O
and	O
converting	O
files	O
on	O
the	O
fly	O
.	O
</s>
<s>
Additionally	O
,	O
the	O
7400	O
has	O
enhanced	O
support	O
for	O
symmetric	B-Operating_System
multiprocessing	I-Operating_System
(	O
SMP	B-Operating_System
)	O
thanks	O
to	O
an	O
improved	O
cache	O
coherency	O
protocol	O
(	O
MERSI	B-General_Concept
)	O
and	O
a	O
64-bit	O
floating	B-General_Concept
point	I-General_Concept
unit	I-General_Concept
(	O
FPU	O
)	O
,	O
derived	O
in	O
part	O
from	O
the	O
604	O
series	O
.	O
</s>
<s>
The	O
603	O
series	O
had	O
a	O
32-bit	O
FPU	O
,	O
which	O
took	O
two	O
clock	O
cycles	O
to	O
accomplish	O
64-bit	O
floating	B-Algorithm
point	I-Algorithm
arithmetic	I-Algorithm
.	O
</s>
<s>
The	O
PowerPC	B-General_Concept
G4	I-General_Concept
family	O
supports	O
two	O
bus	O
technologies	O
,	O
the	O
older	O
60x	B-General_Concept
bus	O
which	O
it	O
shares	O
with	O
the	O
PowerPC	B-General_Concept
600	I-General_Concept
and	O
PowerPC	B-Device
7xx	I-Device
families	O
,	O
and	O
the	O
more	O
advanced	O
MPX	O
bus	O
.	O
</s>
<s>
Devices	O
that	O
utilize	O
the	O
60x	B-General_Concept
bus	O
can	O
be	O
made	O
compatible	O
with	O
either	O
6xx	O
or	O
7xx	O
processors	O
,	O
enabling	O
a	O
wide	O
variety	O
of	O
offerings	O
and	O
a	O
clear	O
and	O
cheap	O
upgrade	O
path	O
while	O
keeping	O
compatibility	O
issues	O
at	O
a	O
minimum	O
.	O
</s>
<s>
The	O
PowerPC	B-Architecture
7410	O
"	O
Nitro	O
"	O
is	O
a	O
low-power	O
version	O
of	O
the	O
7400	O
but	O
it	O
was	O
manufactured	O
at	O
180nm	O
instead	O
of	O
200nm	O
.	O
</s>
<s>
It	O
debuted	O
in	O
the	O
PowerBook	B-Operating_System
G4	I-Operating_System
on	O
9	O
January	O
2001	O
.	O
</s>
<s>
This	O
feature	O
was	O
used	O
by	O
embedded	B-Architecture
systems	I-Architecture
vendors	O
such	O
as	O
Mercury	B-Application
Computer	I-Application
Systems	I-Application
.	O
</s>
<s>
The	O
PowerPC	B-Architecture
7450	O
"	O
Voyager	O
"	O
/	O
"	O
V'ger	O
"	O
was	O
the	O
only	O
major	O
redesign	O
of	O
the	O
G4	B-General_Concept
processor	I-General_Concept
.	O
</s>
<s>
The	O
AltiVec	B-General_Concept
unit	O
was	O
improved	O
with	O
the	O
7450	O
;	O
instead	O
of	O
executing	O
one	O
vector	O
permute	B-Algorithm
instruction	I-Algorithm
and	O
one	O
vector	O
ALU	O
(	O
simple	O
int	O
,	O
complex	O
int	O
,	O
float	B-Algorithm
)	O
instruction	O
per	O
cycle	O
like	O
7400/7410	O
,	O
the	O
7450	O
and	O
its	O
Motorola/Freescale	O
-followers	O
can	O
execute	O
two	O
arbitrary	O
vector	O
instructions	O
simultaneously	O
(	O
permute	O
,	O
simple	O
int	O
,	O
complex	O
int	O
,	O
float	B-Algorithm
)	O
.	O
</s>
<s>
It	O
was	O
introduced	O
with	O
the	O
733MHz	O
Power	B-Device
Mac	I-Device
G4	I-Device
on	O
9	O
January	O
2001	O
.	O
</s>
<s>
Early	O
AmigaOne	B-Device
XE	O
computers	O
were	O
shipped	O
with	O
the	O
7451	O
processor	O
.	O
</s>
<s>
The	O
PowerPC	B-Architecture
7455	O
"	O
Apollo	O
6	O
"	O
was	O
introduced	O
in	O
January	O
2002	O
.	O
</s>
<s>
It	O
came	O
with	O
a	O
wider	O
,	O
256-bit	O
on-chip	O
cache	O
path	O
,	O
and	O
was	O
fabricated	O
in	O
Motorola	O
's	O
0.18μm	O
(	O
180nm	O
)	O
HiPerMOS	O
process	O
with	O
copper	O
interconnects	O
and	O
SOI	B-Algorithm
.	O
</s>
<s>
The	O
PowerPC	B-Architecture
7447	O
"	O
Apollo	O
7	O
"	O
is	O
slightly	O
improved	O
from	O
the	O
7450/55	O
,	O
it	O
has	O
a	O
512	O
KB	O
on-chip	O
L2	O
cache	O
and	O
was	O
manufactured	O
in	O
a	O
130	O
nm	O
process	O
with	O
SOI	B-Algorithm
,	O
hence	O
drawing	O
less	O
power	O
.	O
</s>
<s>
With	O
the	O
7447A	O
,	O
which	O
introduced	O
an	O
integrated	O
thermal	O
diode	O
as	O
well	O
as	O
DFS	O
(	O
dynamic	B-General_Concept
frequency	I-General_Concept
scaling	I-General_Concept
)	O
Freescale	O
was	O
able	O
to	O
reach	O
a	O
slightly	O
higher	O
clock	O
.	O
</s>
<s>
The	O
7447B	O
is	O
effectively	O
a	O
7447A	O
with	O
even	O
higher	O
frequency	O
scaling	O
,	O
with	O
clock	O
rates	O
up	O
to	O
1.7GHz	O
officially	O
and	O
easily	O
up	O
to	O
2.4GHz	O
through	O
overclocking	B-Application
.	O
</s>
<s>
The	O
only	O
companies	O
that	O
offer	O
the	O
7457	O
in	O
the	O
form	O
of	O
upgrades	O
for	O
the	O
Power	B-Device
Mac	I-Device
G4	I-Device
,	O
iMac	B-Device
G4	I-Device
,	O
and	O
Power	B-Device
Mac	I-Device
G4	I-Device
Cube	I-Device
are	O
Giga	O
Designs	O
,	O
Sonnet	O
Technology	O
,	O
Daystar	O
Technology	O
(	O
they	O
use	O
the	O
7457	O
only	O
for	O
iMac	B-Device
G4	I-Device
upgrades	O
)	O
and	O
PowerLogix	O
.	O
</s>
<s>
The	O
Pegasos	B-Device
computer	O
platform	O
from	O
Genesi	O
also	O
uses	O
7447	O
in	O
its	O
Pegasos-II/G4	O
.	O
</s>
<s>
The	O
7457	O
is	O
often	O
used	O
to	O
repair	O
an	O
AmigaOne	B-Device
XE	O
CPU	O
module	O
;	O
some	O
AmigaOS	B-Application
software	O
with	O
the	O
7457	O
installed	O
may	O
mistake	O
the	O
AmigaOne	B-Device
for	O
a	O
Pegasos	B-Device
II	O
computer	O
as	O
there	O
were	O
never	O
any	O
official	O
7457	O
boards	O
released	O
by	O
Eyetech	O
.	O
</s>
<s>
The	O
PowerPC	B-Architecture
7448	O
"	O
Apollo	O
8	O
"	O
is	O
an	O
evolution	O
of	O
the	O
PowerPC	B-Architecture
7447B	O
announced	O
at	O
the	O
first	O
Freescale	O
Technology	O
Forum	O
in	O
June	O
2005	O
.	O
</s>
<s>
It	O
was	O
fabricated	O
in	O
a	O
90nm	O
process	O
with	O
copper	O
interconnects	O
and	O
SOI	B-Algorithm
.	O
</s>
<s>
PowerPC	B-Architecture
7448	O
users	O
were	O
:	O
</s>
<s>
In	O
2004	O
,	O
Freescale	O
renamed	O
the	O
G4	O
core	O
to	O
e600	O
and	O
changed	O
its	O
focus	O
from	O
general	O
CPUs	O
to	O
high-end	O
embedded	O
SoC	B-Architecture
devices	O
,	O
and	O
introduced	O
a	O
new	O
naming	O
scheme	O
,	O
MPC86xx	O
.	O
</s>
<s>
The	O
7448	O
was	O
to	O
be	O
the	O
last	O
pure	O
G4	O
and	O
it	O
formed	O
the	O
base	O
of	O
the	O
new	O
e600	O
core	O
with	O
a	O
seven-stage	O
,	O
three-issue	O
pipeline	O
,	O
and	O
a	O
powerful	O
branch	B-General_Concept
prediction	I-General_Concept
unit	I-General_Concept
which	O
handles	O
up	O
to	O
sixteen	O
instructions	O
out-of-order	O
.	O
</s>
<s>
It	O
has	O
an	O
enhanced	O
AltiVec	B-General_Concept
unit	O
capable	O
of	O
limited	O
out-of-order	B-General_Concept
execution	I-General_Concept
and	O
a	O
1MB	O
L2	O
cache	O
.	O
</s>
