Memory buying guide – including 1.35V memory for Romley

When will low voltage HyperCloud be available ?

We examine the impact of low voltage HyperCloud, and why it was not available at 16GB levels.

And why availability of 1.35V is tied to the arrival of 32GB HyperCloud.

Additionally, we establish a more nuanced “rule of thumb” for choosing memory:

for 1.5V – “above 256GB requires HyperCloud”
for 1.35V – “above 384GB requires HyperCloud”

This is meant as an update to the article:

https://ddr3memory.wordpress.com/2012/06/25/memory-buying-guide-when-to-use-rdimms/
Memory buying guide – when to use RDIMMs on Romley ?
June 25, 2012

Availability of 32GB HyperCloud and low voltage

HyperCloud is available at IBM/HP at 1.5V (no 1.35V yet), and 32GB HyperCloud will be available mid-2012.

What will be the impact of low voltage availability ?

32GB HyperCloud are due mid-2012 (according to Netlist conference call).

From NLST’s Q1 2012 CC:

http://seekingalpha.com/article/592411-netlist-s-ceo-discusses-q1-2012-results-earnings-call-transcript
Netlist’s CEO Discusses Q1 2012 Results – Earnings Call Transcript
May 15, 2012

We’re working to expand our qualification footprint at both IBM and HP as we increase the number of server platforms available to ship with 16-gigabyte HCDIMMs. We’re also working together with our OEM partners to qualify the next level of density 32-gigabyte HCDIMMs in Romley-based servers. We expect this testing to be completed over the next few months.

Richard Shannon – Craig-Hallum Capital

Hi, everybody. I just have a quick question, I guess, first of all, I want to say congratulations on the HP announcement you put out today. Curious, since last quarter you’ve announced both IBM and HP — publicly announced usage of HyperCloud, but it’s been at the 16-gig capacity and the 1.5 vault level. Curious about the progress towards getting 32 gigs and 1.35 vaults out there, what kind of timing you expect on that? And how important you see those products relative to the ones you’ve already qualified with those two key vendors?

Chris Lopes

Sure. Hi, Richard, this is Chris Lopes. Well, both those customers that you mentioned have seen samples of 32-gig, are very excited about it, they’re in the process of getting their plans together for qualification. So we’ve had very positive early test results, and we think that will complete this coming quarter.

Netlist has not indicated if 1.35V (low voltage) versions of HyperCloud will be available.

They have however said that they are working to qualify HyperCloud on more servers (than the current HP DL360p and DL380p and IBM x3650 M4).

And plan on bringing the 32GB HyperCloud on IBM/HP mid-2012.

We can however examine what memory choices would be for 1.35V if HyperCloud becomes available at 1.35V.

Historical performance of HyperCloud at 1.35V

We know what speeds HyperCloud has historically delivered at 1.35V.

For both 16GB and 32GB HyperCloud:

at 1.5V:
1 DPC at 1333MHz – same as LRDIMM
2 DPC at 1333MHz – same as LRDIMM
3 DPC at 1333MHz – better than LRDIMM 1066MHz

at 1.35V:
1 DPC at 1333MHz – same as LRDIMM
2 DPC at 1333MHz – same as LRDIMM
3 DPC at 1066MHz – same as LRDIMM

The achievable speeds at 1.35V are similar to those of LRDIMMs.

LRDIMMs bring with them a set of problems:

– HyperCloud latency, cost and IP superiority trumps LRDIMMs
– usually they are priced similarly (IBM memory price list)

On the risk factors for LRDIMM:

https://ddr3memory.wordpress.com/2012/06/05/lrdimms-future-and-end-user-risk-factors/
LRDIMMs future and end-user risk factors
June 5, 2012

https://ddr3memory.wordpress.com/2012/06/15/why-are-lrdimms-single-sourced-by-inphi/
Why are LRDIMMs single-sourced by Inphi ?
June 15, 2012

So one would prefer to use the HyperCloud if available on your server.

Netlist has had 1.35V 16GB HyperCloud available for some time:

http://www.prnewswire.com/news-releases/netlist-introduces-low-voltage-hypercloud-industrys-first-135v-virtual-rank-memory-module-92165154.html
Netlist Introduces Low-Voltage HyperCloud
April 27, 2010

LAS VEGAS, April 27, 2010 — Today at Interop 2010, Netlist, Inc. introduced its low voltage HyperCloud, the industry’s highest density 1.35V virtual rank memory module. Supporting up to 384GB of DRAM populated in a single dual socket server, low voltage HyperCloud now offers datacenters the ability to realize up to 19 percent in memory power savings when compared with traditional 1.5V solutions.

Low voltage HyperCloud memory features low latency and supports 3 DIMMs per channel (3 DPC) at a transfer rate of 1067 MT/s (backward compatible with 3 DPC 1333 MT/s at 1.5V) to provide maximum memory bandwidth and increased server performance versus standard registered DIMMs (RDIMMs) at 1.35V. It also utilizes Netlist’s patented rank multiplication ASIC technology to fully populate three memory channels with 16GB 2 virtual rank (vRank) RDIMMs. Four physical ranks are hidden from the memory controller hub and presented as two virtual ranks. Dual socket servers can then be fully populated with twenty-four 16GB 2 vRank RDIMMs (4 DPC) reaching a total capacity of 384GB.

Netlist lists both 1.5V and 1.35V availability for 32GB HyperCloud:

http://www.netlist.com/products/hypercloud/

32GB HyperCloud Brief Product Brief – NEW PDF

Features
– 768GB DRAM 2P server capacity
– 1333MT/s speed for maximum performance
– Low latency distributed architecture
– 1.5V/1.35V support
– JEDEC compatible

Netlist is already selling a low voltage regular VLP RDIMM (leveraging the Planar-X IP which is cheaper to produce) memory for Romley-based IBM blade servers:

http://www.netlist.com/news-and-events/2012-03-06/16gb-4rx4-planar-x-vlp-rdimm-available-on-ibm-blade-center-hx5-servers/
16GB 4Rx4 Planar-X VLP RDIMM Available on IBM Blade Center HX5 Servers
March 6, 2012

Examining the impact on memory choice

Now to examine how availability of 1.35V HyperCloud will impact memory choice.

Since HyperCloud delivers 3 DPC at 1066MHz at 1.35V, there will be some configurations for which HyperCloud is non-viable (for example 16GB RDIMMs (2-rank) perform 3 DPC at 1066MHz at 1.35V also, so better to just use the RDIMM in that case).

Choosing memory for 2-socket servers:

For 1.5V:

256GB or less:

use 16GB RDIMM (2-rank) – 2 DPC – 16 DIMMs
rated at 1600MHz (1.5V)
rated at 1333MHz (1.5V)
achievable bandwidth – same as rated speed

384GB

use 16GB HyperCloud – 3 DPC – 24 DIMMs
rated at 1333MHz (1.5V)
achievable bandwidth – same as rated speed

512GB

use 32GB HyperCloud – 2 DPC – 16 DIMMs
rated at 1333MHz (1.5V)
achievable bandwidth – same as rated speed

768GB

use 32GB HyperCloud – 3 DPC – 24 DIMMs
rated at 1333MHz (1.5V)
achievable bandwidth – same as rated speed

For 1.35V (low voltage):

256GB or less:

use 16GB RDIMM (2-rank) – 2 DPC – 16 DIMMs
rated at 1333MHz (1.35V)
achievable bandwidth – same as rated speed

384GB

use 16GB RDIMM (2-rank) – 3 DPC – 24 DIMMs
rated at 1333MHz (1.35V)
achievable bandwidth – ONE speed grade slower (1066MHz)

NOTE: at 384GB the 1.35V 16GB HyperCloud is non-viable, as the RDIMM suffices

512GB

use 32GB HyperCloud – 2 DPC – 16 DIMMs
rated at 1333MHz (1.35V)
achievable bandwidth – same as rated speed

768GB

use 32GB HyperCloud – 3 DPC – 24 DIMMs
rated at 1333MHz (1.35V)
achievable bandwidth – ONE speed grade slower (1066MHz)

So we can see that at low voltage (1.35V) the achievable bandwidth drops, however the HyperCloud performance trumps all other options (RDIMMs, LRDIMMs) when addressing greater than 384GB memory loading.

For an examination of why low voltage increases the need for load reduction:

https://ddr3memory.wordpress.com/2012/06/01/impact-of-lowered-voltages-in-ddr4/
Impact of lowered voltages in DDR4
June 1, 2012

Summary

We have earlier examined the memory choices for Romley and the process by which you arrive at the best memory to buy at each memory loading level:

https://ddr3memory.wordpress.com/2012/06/25/memory-buying-guide-when-to-use-rdimms/
Memory buying guide – when to use RDIMMs on Romley ?
June 25, 2012

In that examination we arrived at a rule of thumb:

– for 1.5V – “above 256GB requires HyperCloud”.

However, that analysis did not include 1.35V.

With our examination of 1.35V low voltage, we arrive at a more nuanced rule of thumb:

– for 1.5V – “above 256GB requires HyperCloud”.
.
– for 1.35V – “above 384GB requires HyperCloud”

What is interesting is that at 1.35V, the applicability of HyperCloud is in the above 384GB segment (and all using 32GB HyperCloud).

This points to a possible reason for WHY we have not heard about a 1.35V 16GB HyperCloud – there is no applicability of a 1.35V 16GB HyperCloud (non-viable).

However, there is great potential for the 1.35V 32GB HyperCloud – it becomes the preferred memory of choice for above 384GB memory loading on a 2-socket server.

The applicability of 1.35V HyperCloud will thus start with 32GB HyperCloud.

So while Netlist only announced 16GB HyperCloud at 1.5V at the OEMs, one would expect that when Netlist announces 32GB HyperCloud – they will do so for both 1.5V and 1.35V.

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13 Comments

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13 responses to “Memory buying guide – including 1.35V memory for Romley

  1. Pingback: Memory buying guide – when to use RDIMMs on Romley ? | ddr3memory

  2. ddr3memory – since power is a big concern for us, do you think it is better to wait for 1.35V HCDIMM or use 1.35V LRDIMM. Concern is if HCDIMM takes longer than 1 quarter to be released. Any thoughts ?

    • If you need less than or equal to 256GB at 1.5V or 384GB at 1.35V you can just use 16GB RDIMMs (2-rank).

      I assume you are talking about 32GB LRDIMM at 1.35V (since 16GB LRDIMM are non-viable vs. the RDIMMs).

      Yes, NLST has said 32GB HyperCloud will be available mid-2012 at IBM/HP – they have not said that 1.35V will be released, but all indications are that they should – they would be stupid not to as the whole market is available to them to take over at 32GB.

      But someone should get confirmation from Netlist on this – if you do, please post back here.

      By the way, are 32GB LRDIMMs (1.35V) available for delivery right now ? If so, Netlist needs to hurry up it’s 32GB 1.5V/1.35V.

      At 1.35V the speed difference is non-existent between LRDIMM and HyperCloud – however LRDIMMs still have the high latency issues and the IP issues – covered in the “risk factors” paragraphs above (however I DOUBT end-users will ever face recall of LRDIMMs – unless of course JEDEC/Inphi fail to get licensing or something).

      When 32GB HyperCloud will be available at IBM/HP and in 1.35V are questions that need answers – if you get an answer, please post here.

      Also if you can inform about the status of 32GB LRDIMMs i.e. “how available” are they – as they were “Available later in 2012” at Romley launch.

      Thanks.

      • I am not a hardware person, but look at the link:
        http://www-03.ibm.com/systems/x/options/memory/ddr3/specs.html

        Does this table mean 32GB LRDIMM at 1.35V is available ? But this could be only a marketing gimmick ? Maybe it runs at 1.5V on the system ? Need to contact our local IBM rep.

      • quote:
        By the way, are 32GB LRDIMMs (1.35V) available for delivery right now ? If so, Netlist needs to hurry up it’s 32GB 1.5V/1.35V.

        I meant that these WERE listed at Romley launch – but had the caveat “Available later in 2012” – so at what point did they actually become deliverable ? Maybe by now they have started to be available for delivery. Some OEMs other than IBM also seemed to suggest availability later at the time of Romley launch.

        Have you tried to order from IBM/HP – you may get better feedback from the reseller links listed here (by calling – I have talked to some of them via their online chat links – which are quite responsive):

        https://ddr3memory.wordpress.com/2012/05/27/what-are-ibm-hcdimms-and-hp-hdimms/
        What are IBM HCDIMMs and HP HDIMMs ?
        May 27, 2012

        If you find out when 32GB LRDIMMs 1.35V actually became deliverable, please let me know.

        Thanks.

        quote:
        —-
        I am not a hardware person, but look at the link:
        http://www-03.ibm.com/systems/x/options/memory/ddr3/specs.html

        Does this table mean 32GB LRDIMM at 1.35V is available ? But this could be only a marketing gimmick ? Maybe it runs at 1.5V on the system ? Need to contact our local IBM rep.
        —-

        Well that is how LRDIMMs have always been listed at IBM i.e. at 1.35V.

        I doubt they are different from that.

        So no variation there – I may point out some typos on this page though – the 16GB HyperCloud (1.5V) is listed as “Quad Rank” – now this is language that is not used on the IBM/HP docs elsewhere – they all call it 2-rank (even though HyperCloud IS a 4-rank internal that is visible externally as a regular RDIMM at 2-rank – which is why it’s called a “virtual 2-rank” by Netlist).

        In contrast the LRDIMMs in IBM/HP docs have ALWAYS been labelled as “Quad Rank”.

        So I note this one difference on this webpage from previous IBM docs on the subject.

        But otherwise this webpage lists is consistent with the other IBM docs mentioned earlier.

      • By the way, I noticed something I had not before – thanks to the link you mentioned above:

        http://www-03.ibm.com/systems/x/options/memory/ddr3/specs.html
        IBM DDR3 Memory for System x

        Firstly, 32GB RDIMM is NOT available at 1.5V.

        This is confirmed by looking at the IBM memory/price list:

        http://www-304.ibm.com/shop/americas/webapp/wcs/stores/servlet/default/CategoryDisplay?catalogId=-840&storeId=1&langId=-1&dualCurrId=73&categoryId=4611686018425093824

        And so listing the differences in one place:

        – 32GB RDIMM is NOT available at 1.5V.
        – 1600MHz RDIMM (which is achievable at 1.5V but not at 1.35V) are NOT available at 16GB and 32GB (max is 8GB only !!) – thus 1600MHz is NOT a competitor for HyperCloud
        – so 16GB RDIMM (2-rank) max speed is 1333MHz

        This means that if you were thinking of using 16GB at 2 DPC and run it at 1600MHz – you cannot do that.

        So I guess there are such exceptions in the memory availability for various OEMs – as illustrated above for IBM System X.

      • I’ve added an infographic specific to the IBM System X memory choices – is in that infographic article.

      • I’ve added an infographic specific to the IBM System X memory choices – is in that infographic article:

        https://ddr3memory.wordpress.com/2012/06/29/infographic-memory-buying-guide-for-romley-2-socket-servers/
        Infographic – memory buying guide for Romley 2-socket servers
        June 29, 2012

  3. Pingback: Infographic – memory buying guide for Romley 2-socket servers | ddr3memory

  4. Pingback: Memory choices for the IBM System X x3750 M4 servers | ddr3memory

  5. Pingback: Memory for VMware virtualization servers | ddr3memory

  6. Pingback: VLP RDIMMs for virtualization on Blade Servers | ddr3memory

  7. Pingback: HyperCloud to own the 32GB market ? | ddr3memory

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