<s>
NexGen	O
,	O
Inc	O
.	O
was	O
a	O
private	O
semiconductor	O
company	O
based	O
in	O
Milpitas	O
,	O
California	O
,	O
that	O
designed	O
x86	B-Operating_System
microprocessors	I-Operating_System
until	O
it	O
was	O
purchased	O
by	O
AMD	O
in	O
1996	O
.	O
</s>
<s>
NexGen	O
was	O
a	O
fabless	B-Algorithm
design	O
house	O
that	O
designed	O
its	O
chips	O
but	O
relied	O
on	O
other	O
companies	O
for	O
production	O
.	O
</s>
<s>
The	O
company	O
was	O
best	O
known	O
for	O
the	O
unique	O
implementation	O
of	O
the	O
x86	B-Operating_System
architecture	I-Operating_System
in	O
its	O
processors	O
.	O
</s>
<s>
NexGen	O
's	O
CPUs	O
were	O
designed	O
very	O
differently	O
from	O
other	O
processors	O
based	O
on	O
the	O
x86	B-Operating_System
instruction	O
set	O
at	O
the	O
time	O
:	O
the	O
processor	O
would	O
translate	O
code	O
designed	O
to	O
run	O
on	O
the	O
traditionally	O
CISC-based	O
x86	B-Operating_System
architecture	I-Operating_System
to	O
run	O
on	O
the	O
chip	O
's	O
internal	O
RISC	B-Architecture
architecture	O
.	O
</s>
<s>
The	O
architecture	O
was	O
used	O
in	O
later	O
AMD	O
chips	O
such	O
as	O
the	O
K6	B-Architecture
,	O
and	O
to	O
an	O
extent	O
most	O
x86	B-Operating_System
processors	O
today	O
implement	O
a	O
"	O
hybrid	O
"	O
architecture	O
similar	O
to	O
those	O
used	O
in	O
NexGen	O
's	O
processors	O
.	O
</s>
<s>
The	O
technology	O
forms	O
the	O
platform	O
architecture	O
for	O
all	O
of	O
AMD	O
's	O
current	O
microprocessors	B-Architecture
.	O
</s>
<s>
Its	O
first	O
design	O
was	O
targeted	O
at	O
the	O
80386	B-General_Concept
generation	O
of	O
processors	O
.	O
</s>
<s>
But	O
the	O
design	O
was	O
so	O
large	O
and	O
complicated	O
it	O
could	O
only	O
be	O
implemented	O
using	O
eight	O
chips	O
instead	O
of	O
one	O
and	O
by	O
the	O
time	O
it	O
was	O
ready	O
,	O
the	O
industry	O
had	O
moved	O
onto	O
the	O
80486	B-General_Concept
generation	O
.	O
</s>
<s>
Its	O
second	O
design	O
,	O
the	O
Nx586	O
CPU	O
,	O
was	O
introduced	O
in	O
1994	O
,	O
was	O
the	O
first	O
CPU	O
to	O
attempt	O
to	O
compete	O
directly	O
against	O
Intel	O
's	O
Pentium	B-General_Concept
,	O
with	O
its	O
Nx586-P80	O
and	O
Nx586-P90	O
CPUs	O
.	O
</s>
<s>
Unlike	O
competing	O
chips	O
from	O
AMD	O
and	O
Cyrix	O
,	O
the	O
Nx586	O
was	O
not	O
pin-compatible	O
with	O
the	O
Pentium	B-General_Concept
or	O
any	O
other	O
Intel	O
chip	O
and	O
required	O
its	O
own	O
custom	O
NxVL-based	O
motherboard	O
and	O
chipset	O
.	O
</s>
<s>
NexGen	O
offered	O
both	O
a	O
VLB	O
and	O
a	O
PCI	B-Protocol
motherboard	O
for	O
the	O
Nx586	O
chips	O
.	O
</s>
<s>
Like	O
the	O
later	O
Pentium-class	O
CPUs	O
from	O
AMD	O
and	O
Cyrix	O
,	O
clock	O
for	O
clock	O
it	O
was	O
more	O
efficient	O
than	O
the	O
Pentium	B-General_Concept
,	O
so	O
the	O
P80	O
ran	O
at	O
75MHz	O
and	O
the	O
P90	O
ran	O
at	O
83.3MHz	O
.	O
</s>
<s>
Unfortunately	O
for	O
NexGen	O
,	O
it	O
measured	O
its	O
performance	O
relative	O
to	O
a	O
Pentium	B-General_Concept
using	O
an	O
early	O
chipset	O
;	O
improvements	O
included	O
in	O
Intel	O
's	O
first	O
Triton	O
chipset	O
increased	O
the	O
Pentium	B-General_Concept
's	O
performance	O
relative	O
to	O
the	O
Nx586	O
and	O
NexGen	O
had	O
difficulty	O
keeping	O
up	O
.	O
</s>
<s>
Furthermore	O
,	O
PCs	O
identified	O
the	O
Nx586	O
as	O
an	O
80386	B-General_Concept
processor	O
;	O
as	O
a	O
result	O
many	O
applications	O
that	O
require	O
a	O
processor	O
faster	O
than	O
a	O
386	B-General_Concept
will	O
not	O
work	O
unless	O
CPU	O
identification	O
software	O
is	O
active	O
.	O
</s>
<s>
Unlike	O
the	O
Pentium	B-General_Concept
,	O
the	O
Nx586	O
had	O
no	O
built-in	O
math	O
coprocessor	B-General_Concept
;	O
an	O
optional	O
Nx587	B-Device
provided	O
this	O
functionality	O
.	O
</s>
<s>
In	O
later	O
Nx586s	O
,	O
an	O
x87	B-Application
math	I-Application
coprocessor	I-Application
was	O
included	O
on-chip	O
.	O
</s>
<s>
Using	O
IBM	O
's	O
multichip	O
module	O
(	O
MCM	O
)	O
technology	O
,	O
NexGen	O
combined	O
the	O
586	B-General_Concept
and	O
587	O
die	O
in	O
a	O
single	O
package	O
.	O
</s>
<s>
Compaq	O
,	O
which	O
had	O
backed	O
the	O
company	O
financially	O
,	O
announced	O
its	O
intention	O
to	O
use	O
the	O
Nx586	O
and	O
even	O
struck	O
the	O
name	O
"	O
Pentium	B-General_Concept
"	O
from	O
its	O
product	O
literature	O
,	O
demos	O
,	O
and	O
boxes	O
,	O
substituting	O
the	O
"	O
586	B-General_Concept
"	O
moniker	O
,	O
but	O
never	O
used	O
NexGen	O
's	O
chip	O
widely	O
.	O
</s>
<s>
Development	O
of	O
AMD	O
's	O
internal	O
K5	O
successor	O
was	O
halted	O
in	O
favor	O
of	O
continuing	O
from	O
NexGen	O
's	O
Nx686	B-Architecture
designs	O
,	O
eventually	O
becoming	O
K6	B-Architecture
.	O
</s>
