Why are LRDIMMs single-sourced by Inphi ?

Inphi as a single point of failure

UPDATE: added 06/21/2012: added info on Montage
UPDATE: 07/06/2012 – now a Montage 1333MHz version like Inphi

The top 3 buffer chipset makers are Inphi, IDTI and Texas Instruments.

However Inphi is the only supplier of “iMB” LRDIMM buffer chipsets for Romley.

Why is there only one supplier of LRDIMM buffer chipsets ?

The top 3 buffer chipset makers for RDIMMs are:

Texas Instruments

And everyone except Inphi has exited the LRDIMM space for Romley.

LRDIMM buffer chipset makers
May 24, 2012

What are the risks to Inphi ?

Inphi currently faces a significant risk in the courts.

Inphi has unilaterally withdrawn their own retaliatory lawsuit against Netlist (Inphi vs. Netlist) – possibly because of accusations of double-patenting (submitting the same patent using two different sets of authors to two different examiners at the USPTO).

They are still facing Netlist vs. Inphi – which they had stayed by challenging Netlist patents at the USPTO. Recently Netlist patents ‘537 and ‘274 have been re-validated in the reexams with all claims intact. When Netlist vs. Inphi resumes, Inphi will face difficulty as it will not be able to challenge the Netlist patents on load reduction and rank multiplication (which LRDIMMs are based on).

Patents which survive reexam cannot be challenged again on those issues.

The risk exists that the court could issue an injunction against further sale of infringing product or of recall.

The fact that no replacement LRDIMMs may be available in the future can impose restrictions on LRDIMM users which may not have been anticipated.

Since LRDIMMs require that all DIMM slots that are populated ONLY use LRDIMMs – LRDIMMs are non-interoperable with RDIMMs or HCDIMMs – it will become difficult to find replacement parts to replace faulty LRDIMMs.

LRDIMMs future and end-user risk factors
June 5, 2012

Market comparison for Inphi-based LRDIMMs vs. Netlist HCDIMM/HDIMM (HyperCloud)

16GB LRDIMMs cannot compete with 16GB RDIMMs – so 16GB LRDIMMs will not sell, and are generally not being supported by the OEMs.

16GB HyperCloud however does compete well with 16GB RDIMMs at the 3 DPC level. It is available in that configuration (3 DPC at 1333MHz) for the IBM x3650 M4 and the HP DL360p and DL380p high volume data center servers.

What are IBM HCDIMMs and HP HDIMMs ?
May 27, 2012

32GB LRDIMMs will compete well with 32GB RDIMMs (primarily because 32GB RDIMMs will be 4-rank for a few years and 4-rank experiences slowdown at 3 DPC and 2 DPC).

The need for high memory loading and it’s impact on bandwidth
May 24, 2012

However 32GB LRDIMMs will not compete with 32GB HyperCloud. LRDIMMs have high latency issues and unable to run at 1333MHz at 3 DPC on regular servers (i.e. without special BIOS tweaks as in the IBM x3750 M4 servers).

LRDIMM latency vs. DDR4
May 31, 2012

32GB LRDIMM market is expected to be 2%-3% of the market (other estimates go higher also).

The benefit of this is much less for LRDIMMs – Inphi gets $20 or so from each memory module (for the buffer chipset).

In contrast Netlist HyperCloud sells for $500 for 16GB or $1500 for 32GB (32GB HyperCloud available mid-2012). And Netlist gets the full $500-$1500 as revenue.

So the revenue contribution for Netlist vs. Inphi is an order or magnitude higher.

For Netlist, a 2%-3% market for 32GB is a significant market.

Market for HCDIMMs HDIMMs
June 5, 2012

Market opportunity for load reduction
June 6, 2012


Risk factors associated with LRDIMMs are not generally known to end-users.

These risk exist despite LRDIMMs being a JEDEC standard. While LRDIMMs copy from Netlist HyperCloud, DDR4 goes further and copies the symmetric lines and decentralized buffer chipset of the HyperCloud.

DDR4 borrows from LRDIMM use of load reduction
June 8, 2012

JEDEC has known about these IP issues for a while and has chosen to ignore those risks. Instead JEDEC has praised Inphi for their contribution.

JEDEC fiddles with DDR4 while LRDIMM burns
June 7, 2012

For these reasons, Inphi remains the single-source supplier of buffer chipsets for LRDIMMs today for Romley, with no other supplier of LRDIMMs available for Romley.

UPDATE: added 06/21/2012: added info on Montage

It seems another supplier of LRDIMM buffer chipsets has emerged – a company called Montage based in China and funded by Intel Capital.

Hynix is using not only LRDIMM buffer chipsets from Inphi, but also from Montage:

Is Montage another MetaRAM ?
June 21, 2012

Montage supplied LRDIMM buffer chipsets seem to underperform even the Inphi LRDIMM buffer chipsets.

UPDATE: 07/06/2012 – now a Montage 1333MHz version like Inphi

Yet Hynix has chosen to qualify with multiple buffer chipset suppliers – both Montage and Inphi.

Usually memory module players choose one supplier and stick with it – as it minimizes the SKUs they need to manage.

Hynix decision to qualify using two sources might be indicative of a perception of higher risk associated with LRDIMMs.

Picking a Chinese-based company may ensure supply of LRDIMMs – at least for the Chinese market (?) in case Inphi is unable to supply LRDIMM buffer chipsets in the future.


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11 responses to “Why are LRDIMMs single-sourced by Inphi ?

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  8. Pingback: Examining Netlist | ddr3memory

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