The Changing Relationship
of Flash & DRAM SSDs - by Jim Handy, Objective Analysis
It
does us a disservice to compare SSDs made with DRAM and NAND in today's light
and to assume that this is the way things will always be.
The greatest cost component of any SSD is its memory. Flash SSDs use
NAND, and RAM SSDs use DRAM.
NAND has been on a steeper price decline than DRAM for its entire
existence. The price of a gigabyte of DRAM declines (on average) 32% per year.
There are indications that this decline may slow. Meanwhile, NAND's price per
gigabyte declines faster, at an average of 50% per year. While NAND used to be
more costly than DRAM, in 2004 it crossed below DRAM.
Today a gigabyte of NAND costs less than 1/3rd as much as a gigabyte
of DRAM and the gap between the two is growing.
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Large system makers, those most
likely to use RAM SSDs, want to balance resources in their systems to get the
greatest performance per dollar, and they are very likely to use three forms of
mass storage in their systems: RAM, flash, and conventional HDD. Today, with
the 3:1 price difference between NAND and DRAM it makes sense to use a certain
amount of both technologies, but those amounts greatly depend upon the system's
task.
By the end of 2012, when a gigabyte of NAND costs 1/19th as
much as a gigabyte of DRAM, the optimum balance of flash/RAM will be very
different.
System analysts and IT managers need to understand how their
systems use disk storage in order to optimize their balance of flash to RAM.
These users should perform their benchmarks in such a way that they can ride
the downward trends in both RAM and flash pricing to get the highest performance
for the lowest cost, taking advantage of the growing price delta between the two
technologies. |
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see also:-
SSD news
the Fastest SSDs
the SSD Buyers Guide
the Top 10 SSD OEMs
RAM versus Flash SSDs
- which is Best?
SSD Myths and
Legends - "write endurance"
Are MLC SSDs Safe
in Enterprise Server Apps?
Z's Laws - Predicting
Future Flash SSD Performance | |
...2 years
Later:-
Looking for Cheaper Flash SSDs?........................ |
Editor:- July 17, 2009 - "Future
NAND (flash) price reductions will be much less than what we have experienced"
- according the analysis in a new
article
by Lane Mason, Memory Market Analyst at Denali Software.
The
article analyzes the market assumptions, and historic cost base for SLC and MLC
flash (including x4) for various geometries and suppliers - and discusses the
likely cost per GB upto 2103.
In the past 4 - 5 years the price per GB
for flash memory shrank by approximately x100 - but the author warns
that in the next 4 years the price shrink may be in low single digits. |
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"Most of the
low-hanging (technical) fruit for NAND cost-reduction has been picked" -
says Lane Mason in this "must
read" article.
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