<s>
vRPM	B-Device
,	O
or	O
virtual	B-Device
Revolutions	I-Device
Per	I-Device
Minute	I-Device
,	O
was	O
a	O
term	O
for	O
a	O
synthetic	O
measurement	O
of	O
performance	O
introduced	O
by	O
SanDisk	O
for	O
solid	B-Device
state	I-Device
drive	I-Device
(	O
SSD	B-Device
)	O
storage	O
devices	O
inside	O
client	O
PCs	B-Device
.	O
</s>
<s>
vRPM	B-Device
was	O
created	O
to	O
give	O
users	O
a	O
metric	O
to	O
compare	O
SSD	B-Device
performance	O
to	O
the	O
hard	B-Device
disk	I-Device
drive	I-Device
(	O
HDD	O
)	O
and	O
to	O
other	O
SSDs	B-Device
.	O
</s>
<s>
vRPM	B-Device
answers	O
the	O
question	O
:	O
"	O
How	O
fast	O
would	O
you	O
have	O
to	O
spin	O
a	O
virtual	O
HDD	O
to	O
achieve	O
the	O
performance	O
of	O
an	O
SSD	B-Device
in	O
a	O
client	O
PC	O
?	O
"	O
</s>
<s>
It	O
uses	O
a	O
language	O
that	O
users	O
understand	O
,	O
RPM	O
(	O
revolutions	O
per	O
minute	O
)	O
,	O
that	O
is	O
a	O
de	O
facto	O
industry	O
standard	O
to	O
measure	O
the	O
performance	O
of	O
the	O
HDD	O
inside	O
PCs	B-Device
.	O
</s>
<s>
The	O
performance	O
of	O
a	O
storage	O
device	O
can	O
be	O
quantified	O
as	O
the	O
number	O
of	O
Input/Output	B-General_Concept
operations	O
Per	O
Second	O
(	O
IOPS	O
)	O
it	O
achieves	O
.	O
</s>
<s>
NAND	O
flash	O
is	O
used	O
as	O
the	O
non-volatile	B-General_Concept
memory	I-General_Concept
inside	O
SSDs	B-Device
.	O
</s>
<s>
It	O
has	O
faster	O
random	O
read	O
than	O
random	O
write	O
performance	O
,	O
since	O
its	O
write	O
performance	O
is	O
delayed	O
by	O
the	O
need	O
to	O
perform	O
garbage	B-General_Concept
collection	I-General_Concept
to	O
free	O
space	O
for	O
writing	O
.	O
</s>
<s>
However	O
,	O
since	O
NAND	O
flash	O
has	O
no	O
moving	O
parts	O
,	O
the	O
SSD	B-Device
achieves	O
much	O
higher	O
IOPS	O
than	O
a	O
HDD	O
.	O
</s>
<s>
Using	O
this	O
equation	O
,	O
the	O
results	O
for	O
client	O
SSD	B-Device
PC	O
performance	O
are	O
as	O
follows	O
:	O
</s>
<s>
The	O
vRPM	B-Device
performance	O
of	O
an	O
SSD	B-Device
can	O
be	O
calculated	O
as	O
follows	O
:	O
</s>
<s>
Using	O
this	O
calculation	O
,	O
SSD	B-Device
vRPM	B-Device
rates	O
can	O
be	O
shown	O
to	O
be	O
significantly	O
better	O
than	O
HDD	O
RPM	O
rates	O
,	O
particularly	O
in	O
later	O
generation	O
SSDs	B-Device
:	O
</s>
<s>
Despite	O
its	O
early	O
objectives	O
,	O
vRPM	B-Device
has	O
not	O
become	O
broadly	O
supported	O
in	O
the	O
industry	O
and	O
no	O
longer	O
appears	O
on	O
SanDisk	O
's	O
SSD	B-Device
website	O
.	O
</s>
