<s>
Sierra	B-Device
or	O
ATS-2	O
is	O
a	O
supercomputer	B-Architecture
built	O
for	O
the	O
Lawrence	O
Livermore	O
National	O
Laboratory	O
for	O
use	O
by	O
the	O
National	O
Nuclear	O
Security	O
Administration	O
as	O
the	O
second	O
Advanced	O
Technology	O
System	O
.	O
</s>
<s>
Sierra	B-Device
is	O
very	O
similar	O
in	O
architecture	O
to	O
the	O
Summit	B-Device
supercomputer	I-Device
built	O
for	O
the	O
Oak	O
Ridge	O
National	O
Laboratory	O
.	O
</s>
<s>
The	O
Sierra	B-Device
system	O
uses	O
IBM	O
POWER9	B-Device
CPUs	O
in	O
conjunction	O
with	O
Nvidia	B-Device
Tesla	I-Device
V100	O
GPUs	O
.	O
</s>
<s>
The	O
nodes	O
in	O
Sierra	B-Device
are	O
Witherspoon	O
IBM	O
S922LC	O
OpenPOWER	O
servers	O
with	O
two	O
GPUs	O
per	O
CPU	O
and	O
four	O
GPUs	O
per	O
node	O
.	O
</s>
<s>
These	O
nodes	O
are	O
connected	O
with	O
EDR	O
InfiniBand	B-Architecture
.	O
</s>
<s>
In	O
2019	O
Sierra	B-Device
was	O
upgraded	O
with	O
IBM	B-Device
Power	I-Device
System	I-Device
AC922	O
nodes	O
.	O
</s>
<s>
has	O
consistently	O
appeared	O
on	O
the	O
Top500	B-Operating_System
list	O
,	O
peaking	O
at	O
.	O
</s>
