
Ask HN: Why are flash memory prices going down so much faster than RAM? - altoz
You can now buy 128gb USB sticks or SD cards for around $20. Meanwhile, 16 gb RAM sticks still are $100+.<p>Are the performance specifications for RAM that much more stringent? Is the demand for SD cards and USB sticks that much greater that there&#x27;s more economies of scale?
======
keenerd
The obvious answer: flash can hold multiple bits per cell and ram can't.

MLC is half as expensive as SLC. TLC is 33% less expensive than MLC. QLC is
25% less expensive than TLC and 75% cheaper than SLC. Not to mention
transparent compression algos. As the controllers improve you can get more
bits of storage from the same amount of flash for free. Longevity and
reliability suffers, but hey, cheap SSDs!

Ram only gets cheaper by improvements to semiconductor processes, which also
can be applied to make flash cheaper. (Big fat asterisk, those processes are
very different.) While improvements to flash that allow more levels per cell
can't be applied to ram. The price difference between flash and ram will only
continue to grow.

Modern flash is quite "analog". The first company to figure out how to
reliably store 32 voltage levels per cell (Five bits. PLC?) will make a quick
billion.

~~~
tonyplee
Two other factors:

Flash connection protocols (sata, ide) allows much faster evolution
independent what's on the other side of interface.

If you have a new flash tech that's 2,3x better in density/speed, you can
easily deploy it in current generation of high end server in the next few
months.

RAM protocols (DDR2,3,4) must be developed 100% in sync with the CPU vendors.
If the major cpu vendors (Intel, AMD, ARM Soc, Qualcomm) decide they don't
want your new 2,3x better interface speed/density, you have zero chance to
deploy it. It takes years for JEDEC to agree on new memory interface standard.
Your new 2,5,10x better tech's deployment is actually depend on your
competitors agree to allow it to be the new standard.

Flash can have higher latency as trade off if needed. DDR interface's latency
has high impact on the CPU/system benchmark.

~~~
ryao
CPUs typically support larger DIMM sizes than exist at launch. Having to wait
on CPU manufacturers to support larger sizes is probably not an issue. Having
an incredibly small market for those larger sizes probably is more of an
issue. The Things stored in RAM are replaced all the time. The things stored
in flash typically are not replaced, but appended, creating a demand for more.

~~~
peller
I think more what the parent post was getting at is perhaps better visualized:

For flash storage, the hierarchy looks like this:

CPU -> standardized interface (PCIe, SATA) -> Controller Chip -> NAND

For DRAM, it looks like this: CPU -> DRAM

The DRAM controller is (these days[0]) built directly into the CPU, whereas
for flash storage, the NAND controller communicates with the CPU (indirectly)
over a standardized interface. So for flash storage, the designers have
control over which controller chip they use, and as such can change the NAND
technology used at will. They aren't even limited to NAND, if something better
comes along. Whereas with RAM, you can't just plug DDR4 into a CPU that only
"speaks" DDR3. I think that flexibility is the important distinction.

[0] It used to be that the DRAM controller was on the northbridge, which was a
separate chip from the CPU. But for the purposes of performance and power
consumption, the tradeoff with flexibility was made (The Athlon 64 was the
first [consumer?] CPU to put the memory controller directly on-die, and that
was a large part of the reason it crushed the Pentium 4.)

------
astrodust
DRAM type memory uses a completely different process than flash even if
they're both a form of "memory". The performance of DDR-type memory is well
beyond anything in the Flash world.

Today 2GB/s is considered very good for an SSD but that would be brutally slow
for system memory. DDR4 memory is typically 30-60GB/s per bank with the low
end being two-channel, the high end being four.

DRAM has also been the subject of aggressive research and development for
many, many decades while large-scale production of flash is a relatively
recent phenomenon. It's the widespread adoption of smart phones, thinner
notebooks, and ubiquitous USB keychain type devices that as pushed it to the
volumes it's at now.

There's also the concern that DDR memory must have a very high level of data
integrity, bit-flip errors are severely problematic, and it can't wear out
even after trillions of cycles. Flash has more pervasive error correction, and
while wear is a minor concern, it's still possible to exhaust it if you
really, really try.

I'd say the reason flash memory prices are steeply down is the new "3D"
process used by Intel and Samsung has been a big game-changer, allowing for
much higher density. DRAM has seen more gradual evolution through the last few
generations.

~~~
dom0
> There's also the concern that DDR memory must have a very high level of data
> integrity, bit-flip errors are severely problematic, and it can't wear out
> even after trillions of cycles. Flash has more pervasive error correction,
> and while wear is a minor concern, it's still possible to exhaust it if you
> really, really try.

The reason why we can't do the pervasive and extremely aggressive error
correction [1] that is used in flash storage to increase usable densities with
DRAM is that forward error correction (FEC) is based on blocks, so to read a
couple bytes from a block you will have to read the entire block [2], decode
it and then you can have your bytes.

This does not work well for RAM ®

Memory fetching is fundamentally based on cache lines; but the overhead in
both bandwidth and latency(!) to fetch-and-decode, say, 64K instead of 64
_bytes_ would be completely unacceptable in most applications.

[1] It's one of the major factors contributing to device endurance. [2]
Simplification: Practical FEC is multi-tiered, ie. there are different block
sizes involved and multiple layers of EC at these block sizes.

~~~
static_noise
I think you're only half-right here.

You cannot do this kind of error correction it like ECC checking in the CPU
because it would require multiple clocks or too many pins.

You cannot do this kind of error correction across multiple DRAM chips on
board because it would require too many pins.

But you could do this kind of error correction on-chip because you could just
read 1024 bits (or more) in parallel from multiple areas (or even mutliple
stacked silicon slices).

One problem, however, is that each small read would induce a high energy cost
due to the many bits fed into the extensive error correction circuitry. While
it shouldn't be a problem for consecutive reads, random-access would indeed
lead to a high power consumption which in most cases would not be acceptable.

------
paws
For some historical context this is worth remembering:

[https://en.wikipedia.org/wiki/DRAM_price_fixing](https://en.wikipedia.org/wiki/DRAM_price_fixing)

~~~
valarauca1
This should be top.

I purchased 64GB of DDR3 for <$100 a year ago. Now I the prices are >$100 for
32GB of DDR3. DDR4 prices are idiotic ~$100 for 16GB

~~~
gruez
>I purchased 64GB of DDR3 for <$100 a year ago.

I don't think it was ever this cheap

~~~
lightedman
Looking back on my prior receipts, a stick of 8GB DDR3-1600MHz a year ago was
about $12. Currently, lowest price I see is sitting at $21 on pricewatch.com
with Newegg being the seller offering the deal (my receipt is from Portatech.)

~~~
yuhong
>Looking back on my prior receipts, a stick of 8GB DDR3-1600MHz a year ago was
about $12.

This would make a 4Gbit DDR3 chip cost less than a dollar, and I don't think
that DRAMeXchange prices has ever been that low

~~~
Ensorceled
You are responding to somebody who claims to have a receipt with a "I think".
The best way to respond to an anecdote is data, not opinion.

~~~
lightedman
I'm the kind of person that keeps receipts for tax purposes, as all parts I
buy are for business purposes (repairs, fresh builds, etc.)

------
xenadu02
It is not the speed, reliability, or processes.

There are numerous flash manufacturers all racing each other to build out
capacity and increase density because they want to eat the HDD market.

DRAM is controlled by a small cabal, all of whom have multiple convictions for
price fixing and collusion. I believe Hynix shipped some sacrificial C-suite
execs to do prison time in the US over it. To a large degree no one is
building out DRAM fab capacity as well.

DRAM prices have stayed high because the manufacturers want it to stay high
and are colluding (either explicitly or implicitly) to keep prices up. The
capital cost to compete is enormous: many billions before you can make your
first sale. The day you break ground memory prices will mysteriously drop so
low as to make your venture unprofitable, meaning your commercial loans get
called in and you go bankrupt. Everyone understands this and avoids attempting
to compete.

~~~
simonhamp
This is quite controversial and sounds more than a little conspiracy theory-
esque.

While I'm sure this sort of thing goes on, if you could back your statements
up with some evidence it would be really helpful.

What you're suggesting here allows for the possibility that at some point some
tech firm finds creates a way for us to ditch traditional DRAM and use the
cheaper flash storage instead.

My gut tells me there is more to it than politics and capitalism.

~~~
TFortunato
I mean, 5 different companies have pleaded guilty to price-fixing in the DRAM
market, so I don't think what is suggested here is _too_ controversial.

[https://en.wikipedia.org/wiki/DRAM_price_fixing](https://en.wikipedia.org/wiki/DRAM_price_fixing)

~~~
simonhamp
Wow. Thanks for surfacing this!

------
zeta0134
If I had to wager an uneducated guess, I would propose that the recent
mainstream acceptance of Solid State Drives as a viable, affordable
alternative to spinning disk drives, has created a sudden demand in Flash
memory that's caused that industry to thrive.

At least at the retail level in the Best Buy where I worked until recently, I
watched Solid State drives transition from something only high end computers
had to something that was standard even among the lower priced value machines.
We had customers complaining about the smaller drive sizes because they were
so accustomed to the gigantic storage offered by the spinning disk media at
its height in popularity.

I'd love someone with more industry knowledge to chime in though, as my own
experience here is pretty limited. This is simply what I've observed in my own
corner of the world.

------
slededit
RAM is only capable of storing one bit per cell. FLASH didn't really take off
until MLC technology came around giving the ability to store multiple bits per
cell which vastly increased the density.

Theoretically RAM could be built that way but it would be much slower. Every
cell read/write would need to go through an ADC/DAC, and the noise is much
higher due to leakage. This slowness isn't much of a problem for FLASH because
its competition was spinning disks that were slow as molasses anyways.

------
candiodari
I think this works by providing a second application for older chip
manufacturing facilities. For SD chip designs, speed and size effectively do
not matter (the controller will matter a hell of a lot more for final speed
than actual storage chips speed). So they're using the chip fabs that everyone
else is abandoning.

As a second bonus, even on old systems SD card circuits are relatively small
(compared to a 5-60" LCD they certainly are). Wafers are round and old wafers
are used to manufacture LCD displays, so small chips can be placed around them
in the manufacturing process and get really good economics by having lots of
manufacturing options.

So same reasons displays are getting cheap, except they're even better. So the
race to the bottom is happening pretty fast for SD cards.

Not entirely sure about this. Might be entirely wrong, but I'm not sure how to
confirm this.

------
CoolGuySteve
Slow SSDs have gone down in price, but fast SSDs are still expensive. For
example, you can get a 500GB Samsung 850 for about $130 but a Samsung 960 evo
costs $250, and then another $100 on top of that for the 960 pro. Those 3
drives range from 600MB/sec to 2222MB/sec linear reads, the fastest costing
the same as a 600MB/sec SSD did 3 years ago.

The demand for slow RAM drops precipitously after the whatever Intel chipsets
use it stop being used in new systems (not sure if the same is true in the
embedded market). For example, nobody's buying DDR2 these days. So the
economies of scale dissipate and fabs retool faster.

So while both devices have economies of scale, SSDs have an extra dimension to
their demand curve for performance that allows for slower higher density chips
to still be profitable.

------
haberman
A question that seems related: what the heck is up with memristors? The
Wikipedia page
([https://en.wikipedia.org/wiki/Memristor](https://en.wikipedia.org/wiki/Memristor))
says that memristors are estimated for commercial viability in 2018, and have
been built in prototype, but _also_ says that there are serious doubts about
whether memristors can possibly exist in physical reality! What gives?

~~~
awalton
Perhaps find better sources than Wikipedia? You can buy Memristors now, but
it's going to be many many years before they get up to densities you'd expect
in modern computing systems. (See sites like
[http://www.bioinspired.net/products-1.html](http://www.bioinspired.net/products-1.html)
or [http://knowm.org/product/](http://knowm.org/product/)).

------
ksec
1\. There little demand for more memory. 2\. There are only a few Memory
makers left on the market. 3\. Moore's Law no longer applicable, smaller
transistor isn't necessarily cheaper any more. 4\. You can have a Bad NAND,
you dont want a Bad memory.

China has decided to pour in 10s of Billions into the NAND and DRAM industry
by 2020, until then the price should very much stable / predictable.

------
markhahn
Why does the OP imply that there is some relation between the two products?
It's true that both use litho and si, but they are dramatically different,
internally.

Think of flash as a consumable media - it is, since each cell can only be
erased a few hundred times. After all, that's what it means when the vendor
says "200TBW for 256G device": you can expect 7-800 cycles per cell. This is
also why vendors are pushing capacity so hard: it lets them push down the
price while at the same time not needing to improve endurance.

So in some sense, the answer is "endurance", since the physics of flash
erasure necessitate high capacity, and no one would buy the extra capacity
unless it were also relatively cheaper. Whereas DRAM doesn't wear out...

~~~
dhimes
OP is simply asking.

------
static_noise
After reading through the answers here, I don't think the real answer has been
given.

Is it the technology?

* Flash cells can store more data an be produced cheaper per cell. But they are more complex to read out and slower.

This can explain some factor, but the factor of 40 given by OP probably not.

* Flash and DRAM probably use different processes.

This could explain a bit but look at the next point...

* DRAM has a much longer history and (at least in the beginning) much higher capital investment.

...which means that DRAM should have the technological advantage. At least
through economies of scale.

Is the cumulative investment in flash research already much bigger compared to
DRAM research?

Is the process used to produce flash memory so much easier?

Is it the market?

* Obviously people pay the price.

* With DRAM people are hungry for performance more than they are for size.

* We already have more than enough DRAM. The latest MacBookPro demonstrates that 16 GB DRAM is enough for just about everybody but flash storage goes up to 1 TB.

* Of those 16 GB DRAM the speed and power consumption are much more important than the raw size.

Coming back to the cumulative investment. I think that the primary pain point
for flash has been the price per GB. Flash could be stronger, faster, more
reliable, less power consuming but those are all secondary. It is fast and
reliable enough by using very complex RAID controllers. The power consumption
is not as bad as HDDs already use a lot and the data mostly just sits around.
The main driving point is the price per GB. This is where the money goes in
flash development.

On the other hand for DRAM, after some point, it is mostly speed and power
driven. Reliability has to be comparatively high as every cell must work over
years. Size is mostly increased by improving semiconductor processes where
flash probably uses a lot of the same technology. Using the layer stacking
technologies of flash is probably not yet applicable because it is not
reliable enough and not compatible with the cell layout, maybe it never will.

If we really were hungry for so much RAM we would probably get it. But we
aren't. It's good enough. Progress slows down.

~~~
raverbashing
You're thinking like an MBA and dismissing the biggest factors

Writing to DRAM is much, much faster than writing to SSD, also reliability (in
the sense that you can use chips with defective cells in SSDs).

You mentioned those factors but you're not giving them enough importance.
Market factors are important, but the price is not going to be less than cost.

~~~
static_noise
I'm thinking like an MBA here because that's how you have to think in order to
reason about the price something has.

Yes, those factors are important! But are they also the main driver of cost? I
don't know.

Could we have speed, reliabaility and size? That is a technological question.
I don't have the answer to that.

Would enough people care to pay for speed, reliability and size? That's more
of an MBA question and the answer probably is no.

The example given is: People pay extra to have 1 TB of flash in their machine
but they are OK with only having 16 GB of RAM. The priority is even to have a
lower power consumption instead of having 32 GB of RAM.

While you are right that we maybe cannot deliver the technology on a pure
technological stance, you kind of miss the point. Even if we could, we
wouldn't do it because of the MBAs driving the fincances in a certain
direction based on (perceived) market forces.

~~~
raverbashing
The question was: "Why are flash memory prices going down so much faster than
RAM?"

Answer: because there are (technological) ways of making it cheaper (and
probably slower/less reliable, but not much), as well as economy of scale
factors

Why DRAM doesn't get cheaper: because it has to follow much stricter
requirements.

The question itself is naive. It thinks "megabytes of memory" are the same
thing regardless of form factor

> Would enough people care to pay for speed, reliability and size? That's more
> of an MBA question and the answer probably is no.

Yes, probably not. Not the masses at least. Unless they buy Apple, they
(still) care about this mostly, apart from adapter shenanigans

------
nickpsecurity
Looking at Hynix's financials, they're making enough money to reduce the cost
of RAM quite a bit. Looks like it's just them maximizing their profit as one
would expect. I assume it's similar for the rest. As always with for-profit
firms selling hardware or I.P..

~~~
ams6110
Unless you're suggesting collusion, that doesn't seem to make sense. Prices
should fall in a competitive market, regardless of what profit a manufacturer
would ideally like to maximize.

~~~
nickpsecurity
Collusion has already happened in this market. I don't need that, though. I've
observed a pattern in a lot of markets where big players, esp wielding
patents, will turn into cartels (intentional or emergent) that act in both
individual self-interest and collective self-interest. A race to the bottom
wouldn't benefit any of them. So, they compete in little ways to fight for
market share but make sure the business models keep the profits up.

The telecoms, both cellular and ISP's, are where this is most obvious where
the compete in the most incremental way saying its impossible to do anything
else. Then, a small play comes in doing what they're doing... sometimes the
same way... with more benefit at a tiny fraction of the cost. Suddenly, they
can afford to do the same with their existing infrastructure. Real competition
would've brought in unlimited plans in cell phones or gigabit in broadband
much sooner for similar or lower prices.

The largest vendors of RAM are likely a cartel in practice. It's the best
outcome for each of them to not race to the bottom. They don't even need to
talk to know that. That they can reinforce it with patents they're more likely
to have than the smaller players is icing on the cake.

~~~
yuhong
Objective Analysis has an entire report on this: [http://objective-
analysis.com/Reports.html#Consolidation](http://objective-
analysis.com/Reports.html#Consolidation)

~~~
nickpsecurity
Appreciate it. Going by abstracts, it looks like there's a cost advantage to
NAND, the DRAM people are greedy cartels, and might have to merge to reduce
costs. Looks like the greed is backfiring but we must remember CEO's and
boards focus on short-term due to incentives. They might still "win" even if
the firms start losing.

------
kabdib
An additional point: People don't know the quality of the flash they are
buying. You're seeing bottom-bin crappy parts made to look better than they
are with ECC. You're also NOT seeing data retention; that cheap USB stick may
develop unreadable blocks sooner (this is much more likely with TLC and QLC,
where the difference between two bit values can be measured in the hundreds or
even dozens of trapped electrons).

------
deathhand
RAM is written to faster than any other component other than the onboard
processor cache.

------
smitherfield
Read/write speeds for DRAM are much faster than flash (although the gap is
closing and the day may soon come where computers are sold with flash storage
but no DRAM, and the distinction between memory and storage is done away
with).

DRAM is also a much more mature technology than flash is, so more of the low-
hanging fruit for improvement has already been taken advantage of.

------
eschutte2
RAM is more expensive to produce in general (more transistors, more stringent
specs as you mentioned), but as to rate of change, that seems more likely to
be due to competitive pressures and maybe more rapidly increasing demand for
flash in recent years versus RAM.

------
tjpaudio
All technical reasons aside, it has got to be mostly demand. I can't see
computers coming pre-configured with more than 64gb, but for storage there is
increasingly more demand as the price reaches parity with spinning disks. One
thing that is true is we are as storage-hungry as ever. High res photos
created by every phone, companies logging every minute process in hopes of
using it for analysis later... Our need for storage vastly outstrips our need
for RAM.

------
ryao
The market for DRAM is relatively mature while the market for flash is still
developing as it canabalizes the hard drive market. Consequently, you see
flash taking advantage of newer processes and techniques first as flash
manufacturers aim for ever greater volumes in pursuit of profits.

------
yuhong
I think NAND flash is more flexible in terms of design than DRAM is, for
example 3D NAND. NAND flash generally communicate through a separate
controller that uses for example the SATA or USB buses, while the DRAM
controller is built into the CPU or chipset.

------
bitJericho
And here I am with 24gb ecc ram for 40 bucks on eBay. Workstation PCs ftw!

------
sushirain
This is the relevant chart:

[http://www.jcmit.com/mem2015.htm](http://www.jcmit.com/mem2015.htm)

DIMM seems to go down slower lately.

