
Micron Kicks Off Mass Production of 12 Gb DRAM Chips - rbanffy
https://www.anandtech.com/show/13569/micron-kicks-off-mass-production-of-12-gb-lpddr4x-dram-chip
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yohann305
Google said 40% of their data server operating cost comes from paying for
energy _, it makes business sense to switch to this type of DRAM.

_ I couldn't find the actual youtube video where a google employee shows the
40% energy cost, if you do, please link it. Meanwhile here is another graph
that is somewhat similar: [https://perspectives.mvdirona.com/2008/11/cost-of-
power-in-l...](https://perspectives.mvdirona.com/2008/11/cost-of-power-in-
large-scale-data-centers/)

~~~
adrr
I am not an expert on microchips but looking at Apple's A12 vs Intel chips in
terms of power and energy usage. Wouldn't the industry really benefit moving
away from X86 architecture to something else in terms of reducing power
consumption? These savings could be passed to users of cloud providers.

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jjeaff
We have about 40 years of software development on x86. I'm not even sure we
could reuse any of that when moving to a new architecture.

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noir_lord
Does that matter for some cases.?

Linux supports arm and we have massive companies where economies of scale and
a Linux/OSS plus their code could all be cross compiled, I mean if your the
average biggish none tech company then yeah you might be stuck on x86 because
of windows but that isn't everyone.

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zitterbewegung
In any organization if you have an internal tool or software it’s not like you
can press a button and make sure it is cross compiled to ARM from x86. That is
a huge and expensive undertaking.

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phkahler
>> In any organization if you have an internal tool or software it’s not like
you can press a button and make sure it is cross compiled to ARM from x86.
That is a huge and expensive undertaking.

That depends on the software. Many linux distributions can be compiled for
x86, ARM, PPC, RISC-V, and even some others. Cross compiling is not difficult
if your software is written with even a little of that in mind. Windows itself
used to be available for 3 or 4 instruction sets - and an OS requires low
level hardware support. Applications should be largely target independent.

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kevin_thibedeau
Lots of x86 code plays fast and loose with alignment which will blow up on
ARM.

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monocasa
Modern big ARMs let you play fast and loose with alignment as well.

Hell, a CortexM3 lets you have unaligned loads and stores too.

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jschwartzi
Even if they don't you can just turn unaligned access emulation on in your OS
kernel. This was a thing in QNX and is also a thing in Linux.

~~~
monocasa
I think it's fair to not want to turn that on in the kernel on chips that
don't support it in servers. It's really expensive on those kinds of cores to
trap into the kernel (a KPTI makes it dramatically more expensive).

That being said, server cores with their long me or pipelines are the most
likely to not have an issue with unaligned access, so it's probably a moot
point.

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elipsey
I hope these exciting advances in science and engineering will lead to... DRAM
that costs the same as several years ago.

~~~
reasonablemann
It makes you wonder what advances in science and engineering have been stalled
because of DRAM costs. Particularly in countries with less money to throw at
research etc.

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akulbe
12GB seems an odd number, when it's usually multiples of 8. Anyone else think
that? I wonder if it's because of size constraints?

~~~
wmf
Phones want 6 GB so they're making 1.5 GB chips. Apparently 4x 1.5 GB is
cheaper than 3x 2 GB, probably because of yield. I imagine it complicates the
address decode slightly but that's it.

This reminds me of triple-core processors that were "inconceivable" right
until they shipped.

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dsr_
Were there _any_ 3-core processors which were not de-rated 4-core processors?

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equalunique
PS3 had a 9-core (3*3).

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retromario
The PS3 had a PowerPC main core cpu and a 8 core cell chip. Of the 8 SPU
cores, only 6 were available to developers as one was reserved for OS
functions and the other, ironically enough, was held back for yield purposes.

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thomastjeffery
Probably a good idea to change the title from "Gb" to "Gbit" to avoid
ambiguity.

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Klasiaster
Is this type of RAM still having rowhammer memory corruption effects?

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masklinn
LPDDR4 has some mitigation for rowhammer, and LPDDR4X is a variant of it. So I
don't know that it's immune, but it should be more resilient.

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jakobegger
Are those the chips in the new iPad Pro? Would make sense since according to
reports the 1TB iPads have 6GB RAM.

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userbinator
I hate these "new parts available" announcements that are so vague they don't
even have part numbers.

Fortunately a search at Micron's website reveals that this is the "Z2BM" with
two part numbers, MT29VZZZ7D8DQFSL-046 (containing 2 Z2BM) and
MT29VZZZBD9DQKPR-046 (containing 4 Z2BM). No public datasheets (yet),
unfortunately, I was curious to read a little more.

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1stranger
Does anybody know how many of these could we expect to fit in a Macbook Pro?
My understanding is the power consumption has been a limiting factor.

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Sephr
You can fit exactly zero of these in the MacBook Pro until Intel ships chips
that actually support LPDDR4X (aside from the Cannonlake paper launch).

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Milner08
Or Apple switch them to the A series processors! Although I really cannot see
that happening on the pro lineup anytime soon (Although I think its highly
likely on the air and non-pro MacBooks)

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hmottestad
I read somewhere that it wouldn't actually help at the moment. LPDDR4 on the A
series chips is in the same package as the CPU. From what I understand, this
is the only current way that anyone in the industry is using LPDDR4.

What Intel is promising is LPDDR4 packaged in it's own chip(s) on the
motherboard.

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frou_dh
In the iPads, the RAM is not stacked onto the CPU, it's normal separate chips.
e.g. two Micron here:
[https://d3nevzfk7ii3be.cloudfront.net/igi/WHKDR5ZU6SSQA3qa](https://d3nevzfk7ii3be.cloudfront.net/igi/WHKDR5ZU6SSQA3qa)

~~~
hmottestad
Had to double check that....but you're correct. So now I'm really hoping for a
AX macbook pro. Imagine what the A12X in the newest ipad could push if you
added some nice cooling to it ;)

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tracker1
As long as you aren't using any Adobe software.

