<s>
The	O
Power	B-Device
Mac	I-Device
G5	I-Device
is	O
a	O
series	O
of	O
personal	B-Device
computers	I-Device
designed	O
,	O
manufactured	O
,	O
and	O
sold	O
by	O
Apple	O
Computer	O
,	O
Inc	O
.	O
from	O
2003	O
to	O
2006	O
as	O
part	O
of	O
the	O
Power	B-Device
Mac	I-Device
series	O
.	O
</s>
<s>
When	O
introduced	O
,	O
it	O
was	O
the	O
most	O
powerful	O
computer	O
in	O
Apple	B-Device
's	I-Device
Macintosh	I-Device
lineup	O
,	O
and	O
was	O
marketed	O
by	O
the	O
company	O
as	O
the	O
world	O
's	O
first	O
64-bit	B-Device
desktop	B-Device
computer	I-Device
.	O
</s>
<s>
It	O
was	O
also	O
the	O
first	O
desktop	B-Device
computer	I-Device
from	O
Apple	O
to	O
use	O
an	O
anodized	O
aluminum	O
alloy	O
enclosure	O
,	O
and	O
one	O
of	O
only	O
three	O
computers	O
in	O
Apple	O
's	O
lineup	O
to	O
utilize	O
the	O
PowerPC	B-General_Concept
970	I-General_Concept
CPU	O
,	O
the	O
others	O
being	O
the	O
iMac	B-Device
G5	I-Device
and	O
the	O
Xserve	O
G5	B-Device
.	O
</s>
<s>
Three	O
generations	O
of	O
Power	B-Device
Mac	I-Device
G5	I-Device
were	O
released	O
before	O
it	O
was	O
discontinued	O
as	O
part	O
of	O
the	O
Mac	B-Device
transition	I-Device
to	I-Device
Intel	I-Device
processors	I-Device
,	O
making	O
way	O
for	O
its	O
replacement	O
,	O
the	O
Mac	B-Device
Pro	I-Device
.	O
</s>
<s>
The	O
Mac	B-Device
Pro	I-Device
retained	O
a	O
variation	O
of	O
the	O
G5	B-Device
's	O
enclosure	O
design	O
for	O
seven	O
more	O
years	O
,	O
making	O
it	O
among	O
the	O
longest-lived	O
designs	O
in	O
Apple	O
's	O
history	O
.	O
</s>
<s>
Officially	O
launched	O
as	O
part	O
of	O
Steve	O
Jobs	O
 '	O
keynote	O
presentation	O
at	O
the	O
Worldwide	O
Developers	O
Conference	O
in	O
June	O
2003	O
,	O
the	O
Power	B-Device
Mac	I-Device
G5	I-Device
was	O
introduced	O
with	O
three	O
models	O
,	O
sharing	O
the	O
same	O
physical	O
case	O
,	O
but	O
differing	O
in	O
features	O
and	O
performance	O
.	O
</s>
<s>
Although	O
somewhat	O
larger	O
than	O
the	O
G4	O
tower	B-General_Concept
it	O
replaced	O
,	O
the	O
necessity	O
for	O
a	O
complex	O
cooling	O
system	O
meant	O
that	O
the	O
G5	B-Device
tower	B-General_Concept
had	O
room	O
inside	O
for	O
only	O
one	O
optical	O
drive	O
and	O
two	O
hard	B-Device
drives	I-Device
.	O
</s>
<s>
Steve	O
Jobs	O
stated	O
during	O
his	O
keynote	O
presentation	O
that	O
the	O
Power	B-Device
Mac	I-Device
G5	I-Device
would	O
reach	O
3GHz	O
"	O
within	O
12	O
months.	O
"	O
</s>
<s>
This	O
would	O
never	O
come	O
to	O
pass	O
;	O
after	O
three	O
years	O
,	O
the	O
G5	B-Device
only	O
reached	O
2.7GHz	O
before	O
it	O
was	O
replaced	O
by	O
the	O
Intel	O
Xeon-based	O
Mac	B-Device
Pro	I-Device
,	O
which	O
debuted	O
with	O
processors	O
running	O
at	O
speeds	O
of	O
up	O
to	O
3GHz	O
.	O
</s>
<s>
During	O
the	O
presentation	O
,	O
Apple	O
also	O
showed	O
Virginia	O
Tech	O
's	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
computer	B-Architecture
cluster	I-Architecture
supercomputer	B-Architecture
(	O
a.k.a.	O
</s>
<s>
supercluster	O
)	O
known	O
as	O
System	B-Device
X	I-Device
,	O
consisting	O
of	O
1,100	O
Power	B-Device
Mac	I-Device
G5	I-Device
towers	O
operating	O
as	O
processing	O
nodes	O
.	O
</s>
<s>
The	O
supercomputer	B-Architecture
managed	O
to	O
become	O
one	O
of	O
the	O
top	O
five	O
supercomputers	B-Architecture
that	O
year	O
.	O
</s>
<s>
The	O
computer	O
was	O
soon	O
dismantled	O
and	O
replaced	O
with	O
a	O
new	O
cluster	O
made	O
of	O
an	O
equal	O
number	O
of	O
Xserve	O
G5	B-Device
rack-mounted	O
servers	O
,	O
which	O
also	O
used	O
the	O
G5	B-Device
chip	O
running	O
at	O
2.3GHz	O
.	O
</s>
<s>
The	O
PowerPC	B-General_Concept
G5	I-General_Concept
(	O
called	O
the	O
PowerPC	B-General_Concept
970	I-General_Concept
by	O
its	O
manufacturer	O
,	O
IBM	O
)	O
is	O
based	O
upon	O
IBM	O
's	O
64-bit	B-Device
POWER4	B-Device
microprocessor	O
.	O
</s>
<s>
At	O
the	O
Power	B-Device
Mac	I-Device
G5	I-Device
's	O
introduction	O
,	O
Apple	O
announced	O
a	O
partnership	O
with	O
IBM	O
in	O
which	O
IBM	O
would	O
continue	O
to	O
produce	O
PowerPC	O
variants	O
of	O
their	O
POWER	O
processors	O
.	O
</s>
<s>
The	O
original	O
PowerPC	B-General_Concept
970	I-General_Concept
had	O
50	O
million	O
transistors	O
and	O
was	O
manufactured	O
using	O
IBM	O
CMOS	O
9S	O
at	O
130	O
nm	O
fabrication	O
process	O
.	O
</s>
<s>
CMOS	O
9S	O
is	O
the	O
combination	O
of	O
SOI	B-Algorithm
,	O
low-k	O
dielectric	O
insulation	O
,	O
and	O
copper	O
interconnect	O
technology	O
,	O
which	O
were	O
invented	O
at	O
IBM	O
research	O
in	O
the	O
mid-1990s	O
.	O
</s>
<s>
Subsequent	O
revisions	O
of	O
the	O
"	O
G5	B-Device
"	O
processor	B-General_Concept
have	O
included	O
IBM	O
's	O
PowerPC	O
970FX	O
(	O
same	O
basic	O
design	O
on	O
a	O
90nm	O
process	O
)	O
,	O
and	O
the	O
PowerPC	O
970MP	B-General_Concept
(	O
essentially	O
two	O
970FX	O
cores	O
on	O
one	O
die	O
)	O
.	O
</s>
<s>
Apple	O
refers	O
to	O
the	O
dual-core	O
PowerPC	O
970MP	B-General_Concept
processors	O
as	O
either	O
the	O
"	O
G5	B-Device
Dual	O
"	O
(	O
for	O
single-socket	O
,	O
dual-core	O
configurations	O
)	O
,	O
or	O
Power	B-Device
Mac	I-Device
G5	I-Device
Quad	I-Device
(	O
for	O
dual-socket	B-General_Concept
,	O
four-core	O
configurations	O
)	O
.	O
</s>
<s>
The	O
Power	B-Device
Mac	I-Device
G5	I-Device
line	O
in	O
2006	O
consisted	O
of	O
three	O
,	O
dual-core	O
PowerPC	B-General_Concept
G5	I-General_Concept
configurations	O
,	O
which	O
can	O
communicate	O
through	O
its	O
HyperTransport	B-Device
at	O
half	O
its	O
internal	O
clock	O
speed	O
.	O
</s>
<s>
Each	O
processor	B-General_Concept
in	O
the	O
Power	B-Device
Mac	I-Device
G5	I-Device
has	O
two	O
unidirectional	O
32-bit	O
pathways	O
:	O
one	O
leading	O
to	O
the	O
processor	B-General_Concept
and	O
the	O
other	O
from	O
the	O
processor	B-General_Concept
.	O
</s>
<s>
The	O
processor	B-General_Concept
at	O
the	O
heart	O
of	O
the	O
Power	B-Device
Mac	I-Device
G5	I-Device
has	O
a	O
"	O
superscalar	B-General_Concept
,	O
superpipelined	O
"	O
execution	O
core	O
that	O
can	O
handle	O
up	O
to	O
216	O
in-flight	O
instructions	O
,	O
and	O
uses	O
a	O
128-bit	O
,	O
162-instruction	O
SIMD	B-Device
unit	O
(	O
AltiVec	B-General_Concept
)	O
.	O
</s>
<s>
All	O
modern	O
32-bit	O
x86	O
processors	O
since	O
the	O
Pentium	B-Device
Pro	I-Device
have	O
the	O
Physical	B-General_Concept
Address	I-General_Concept
Extension	I-General_Concept
(	O
PAE	O
)	O
feature	O
,	O
which	O
permits	O
them	O
to	O
use	O
a	O
36-bit	O
physical	O
memory	B-Architecture
address	O
to	O
address	O
a	O
maximum	O
of	O
236	O
bytes	O
(	O
64	O
gigabytes	O
)	O
of	O
physical	O
memory	B-Architecture
,	O
while	O
the	O
PowerPC	B-General_Concept
970	I-General_Concept
processor	B-General_Concept
is	O
capable	O
of	O
addressing	O
242	O
bytes	O
(	O
4	O
terabytes	O
)	O
of	O
physical	O
memory	B-Architecture
and	O
264	O
bytes	O
(	O
16	O
exabytes	O
)	O
of	O
virtual	B-Architecture
memory	I-Architecture
.	O
</s>
<s>
Due	O
to	O
its	O
64-bit	B-Device
processor	I-Device
(	O
and	O
42-bit	O
MMU	B-General_Concept
)	O
,	O
the	O
final	O
revision	O
of	O
the	O
Power	B-Device
Mac	I-Device
G5	I-Device
can	O
hold	O
16GB	O
of	O
Dual-Channel	O
DDR2	O
PC4200	O
RAM	B-Architecture
using	O
eight	O
memory	B-Architecture
slots	O
,	O
with	O
support	O
for	O
ECC	B-Error_Name
memory	B-Architecture
.	O
</s>
<s>
2004	O
October	O
:	O
A	O
new	O
Single	O
1.8	O
reintroduced	O
,	O
with	O
a	O
slower	O
,	O
600MHz	O
HyperTransport	B-Device
,	O
PCI	B-Protocol
bus	I-Protocol
,	O
based	O
upon	O
the	O
iMac	B-Device
G5	I-Device
's	O
architecture	O
(	O
U3lite	O
and	O
Shasta	O
chips	O
)	O
.	O
</s>
<s>
Apple	O
's	O
official	O
name	O
for	O
this	O
machine	O
is	O
"	O
Power	B-Device
Mac	I-Device
G5	I-Device
(	O
Late	O
2004	O
)	O
"	O
.	O
</s>
<s>
2005	O
April	O
:	O
CPU	O
speed	O
increased	O
:	O
Dual	O
2.5GHz	O
→	O
Dual	O
2.7GHz	O
(	O
PCI-X	O
,	O
LC	O
)	O
,	O
Dual	O
2.0GHz	O
→	O
Dual	O
2.3GHz	O
(	O
PCI-X	O
)	O
,	O
Dual	O
1.8GHz	O
→	O
Dual	O
2.0GHz	O
(	O
PCI	B-Protocol
)	O
.	O
</s>
<s>
Newly	O
introduced	O
features	O
were	O
the	O
16x	O
dual-layer	O
SuperDrives	B-Device
across	O
the	O
line	O
and	O
increased	O
storage	O
,	O
up	O
to	O
800GB	O
for	O
the	O
higher-end	O
models	O
.	O
</s>
<s>
2005	O
October	O
:	O
Shift	O
to	O
dual-core	O
processors	O
:	O
Dual	O
2.0GHz	O
→	O
DC	O
2.0GHz	O
,	O
Dual	O
2.3GHz	O
→	O
DC	O
2.3GHz	O
,	O
Dual	O
2.7GHz	O
→	O
Dual	O
DC	O
2.5GHz	O
(	O
termed	O
a	O
Quad	O
Power	B-Device
Mac	I-Device
G5	I-Device
,	O
with	O
four	O
CPU	O
execution	O
cores	O
and	O
more	O
reliable	O
liquid	O
cooling	O
)	O
,	O
all	O
with	O
DDR2	O
memory	B-Architecture
,	O
and	O
PCI	B-Protocol
Express	O
expansion	O
in	O
place	O
of	O
PCI-X	O
.	O
</s>
<s>
The	O
older	O
PCI-X	O
,	O
Dual	O
2.7GHz	O
model	O
remained	O
available	O
for	O
a	O
while	O
,	O
but	O
the	O
slower	O
speed	O
single-core	O
models	O
were	O
discontinued	O
immediately	O
.	O
</s>
<s>
2006	O
August	O
:	O
The	O
Power	B-Device
Mac	I-Device
is	O
replaced	O
by	O
its	O
Intel	O
successor	O
,	O
the	O
Mac	B-Device
Pro	I-Device
.	O
</s>
<s>
Early	O
versions	O
of	O
dual	O
processor	B-General_Concept
G5	B-Device
computers	O
have	O
noise	O
problems	O
.	O
</s>
<s>
B	O
G5	B-Device
.	O
</s>
<s>
This	O
noise	O
problem	O
was	O
not	O
fixed	O
until	O
the	O
dual	O
core	O
generation	O
of	O
G5s	B-Device
was	O
produced	O
,	O
however	O
it	O
did	O
not	O
affect	O
the	O
"	O
Late	O
2004	O
"	O
model	O
(	O
at	O
least	O
there	O
have	O
never	O
been	O
any	O
reports	O
)	O
.	O
</s>
<s>
A	O
common	O
problem	O
among	O
single	O
processor	B-General_Concept
G5s	B-Device
was	O
that	O
the	O
plate	O
of	O
metal	O
soldered	O
to	O
the	O
Logic	O
Board	O
connecting	O
all	O
eight	O
of	O
the	O
RAM	B-Architecture
slots	O
would	O
,	O
over	O
time	O
,	O
expand	O
and	O
contract	O
in	O
such	O
a	O
way	O
that	O
the	O
computer	O
could	O
not	O
boot	O
properly	O
,	O
as	O
it	O
would	O
not	O
detect	O
any	O
RAM	B-Architecture
.	O
</s>
<s>
All	O
2.5GHz	O
and	O
2.7GHz	O
dual	O
processor	B-General_Concept
models	O
and	O
the	O
2.5GHz	O
quad-processor	O
model	O
had	O
a	O
liquid	O
cooling	O
system	O
that	O
consisted	O
of	O
a	O
radiator	O
,	O
coolant	O
pump	O
,	O
and	O
heat	O
exchangers	O
bolted	O
to	O
the	O
processors	O
.	O
</s>
<s>
Semi	O
announced	O
the	O
preliminary	O
pre-production	O
plan	O
of	O
PWRficient	B-General_Concept
processor	B-General_Concept
,	O
there	O
had	O
been	O
persistent	O
rumors	O
that	O
Apple	O
would	O
prepare	O
for	O
its	O
use	O
in	O
its	O
professional	O
line	O
of	O
personal	B-Device
computers	I-Device
.	O
</s>
<s>
Semi	O
promptly	O
delivering	O
processor	B-General_Concept
chips	O
for	O
Apple	O
's	O
personal	B-Device
computer	I-Device
notebook	O
line	O
and	O
possibly	O
desktops	O
.	O
</s>
<s>
Even	O
in	O
2006	O
,	O
Apple	O
did	O
not	O
have	O
a	O
laptop	O
version	O
of	O
the	O
G5	B-General_Concept
processor	I-General_Concept
.	O
</s>
<s>
The	O
processor	B-General_Concept
that	O
would	O
run	O
the	O
personal	B-Device
computers	I-Device
was	O
P.A.	O
</s>
<s>
Semi	O
's	O
preliminarily	O
proposed	O
processor	B-General_Concept
,	O
PWRficient	B-General_Concept
1682M	O
(	O
PA6T-1682M	O
)	O
.	O
</s>
<s>
The	O
version	O
that	O
would	O
be	O
sampled	O
for	O
pre-production	O
at	O
third	O
quarter	O
of	O
2006	O
was	O
a	O
2GHz	O
,	O
dual-core	O
CPU	O
with	O
two	O
DDR2	O
memory	B-Architecture
controllers	O
,	O
2MB	O
of	O
L2	O
cache	B-General_Concept
,	O
and	O
support	O
for	O
8	O
PCI	B-Protocol
Express	O
lanes	O
.	O
</s>
<s>
At	O
the	O
time	O
,	O
the	O
companies	O
were	O
working	O
for	O
PWRficient	B-General_Concept
software	O
.	O
</s>
<s>
Semi	O
's	O
status	O
as	O
a	O
start-up	O
company	O
,	O
seems	O
to	O
have	O
been	O
the	O
final	O
blow	O
to	O
the	O
development	O
of	O
Power	B-Device
Mac	I-Device
computers	O
.	O
</s>
<s>
However	O
,	O
it	O
was	O
also	O
speculated	O
that	O
Apple	O
switched	O
to	O
Intel	O
processor	B-General_Concept
because	O
Apple	O
could	O
no	O
longer	O
abide	O
the	O
constant	O
delays	O
in	O
performance	O
ramp	O
up	O
,	O
desired	O
native	O
Windows	B-Application
compatibility	O
,	O
or	O
it	O
was	O
Apple	O
's	O
strategy	O
to	O
shift	O
its	O
business	O
focus	O
away	O
from	O
desktop	B-Device
computing	I-Device
to	O
iPod	B-Device
(	O
and	O
subsequently	O
iOS	B-Operating_System
)	O
development	O
.	O
</s>
<s>
Semi	O
's	O
engineering	O
resources	O
to	O
develop	O
ARM	O
CPUs	O
for	O
their	O
iPhone	B-Device
,	O
iPod	B-Device
Touch	I-Device
,	O
iPad	B-Device
,	O
and	O
Apple	B-Device
TV	I-Device
product	O
lines	O
;	O
and	O
would	O
go	O
on	O
to	O
eventually	O
come	O
full	O
circle	O
with	O
these	B-Device
designs	I-Device
replacing	I-Device
Intel	I-Device
chips	I-Device
in	O
Macs	B-Device
in	O
2020	O
.	O
</s>
<s>
The	O
PA6T-1682M	O
processor	B-General_Concept
would	O
later	O
be	O
used	O
by	O
the	O
AmigaOne	B-Device
X1000	I-Device
personal	B-Device
computer	I-Device
.	O
</s>
