Awaiting 32GB HCDIMMs

Industry needs availability on a wide range of servers

When 32GB HCDIMMs become available, they will be the memory module of choice in the 32GB segment.

This will be applicable to both the regular Romley servers as well as the non-Intel-POR (plan-of-record) servers like the IBM x3750 M4 server.

The reason is that:

– HCDIMMs are RDIMM-compatible
– HCDIMMs run at higher speed than LRDIMMs
– HCDIMMs outperform LRDIMMs in latency and throughput even when HCDIMMs are run at the lower same speeds as LRDIMM

Their qualification on a wide range of servers is essential for the industry to get access to the best memory available.


HCDIMM vs. LRDIMM comparision

We have previously covered why 32GB HyperCloud will dominate the 32GB space:
HyperCloud to own the 32GB market ?
July 9, 2012

Now we have latency and throughput performance info about LRDIMMs which confirms those observations:
Latency and throughput figures for LRDIMMs emerge
July 26, 2012

Adding in the latency and throughput information to the previous HCDIMM vs. LRDIMM comparision – 32GB HCDIMMs trump 32GB RDIMMs and 32GB LRDIMMs in performance, latency, price and IP issues:

– HCDIMMs are RDIMM-compatible
– LRDIMMs are incompatible with RDIMMs (are a new standard)
– HCDIMMs run at 1333MHz at 3 DPC
– LRDIMMs peak at 1066MHz at 3 DPC
– HCDIMMs when run at a SLOWER 1066MHz at 3 DPC outperform LRDIMMs by 31%/58.2% in latency/throughput
– this means HCDIMMs will trump LRDIMMs even on the non-Intel-POR servers like IBM x3750 M4 server
– HCDIMMs when run at 1333MHz at 3 DPC outperform LRDIMMs by 31%/68.5% in latency/throughput
– HCDIMMs have nearly identical “loaded latency” as RDIMMs (an amazing feat)
– LRDIMMs have abysmally poor latency and throughput
– DDR4 will copy HCDIMM architectural choices (and not LRDIMMs’)
– 32GB HCDIMMs will be cheaper than 32GB RDIMMs/32GB LRDIMMs (use 4Gbit monolithic instead of 4Gbit x 2 DDP)
– Inphi is infringing on Netlist IP in load reduction and rank multiplication when it makes LRDIMMs

Add to that the non-viability of 32GB RDIMMs (4-rank) vs. LRDIMM/HCDIMM:
Non-viability of 32GB RDIMMs
June 20, 2012

And the risk factors for LRDIMMs.

On the risk factors for LRDIMM:
LRDIMMs future and end-user risk factors
June 5, 2012
Why are LRDIMMs single-sourced by Inphi ?
June 15, 2012

And you have 32GB HCDIMM outperforming RDIMMs and LRDIMMs in performance, latency, price and IP issues.


Market for 32GB

The 32GB memory module segment is expected to be 2%-3% of servers, expanding to 10% in 2013.

While Netlist has guided for only a fraction of that market (and will be content with even that), the industry will require that HCDIMMs be universally available on all servers.

For more info on the market for load reduction and rank multiplication:
Market for HCDIMMs HDIMMs
June 5, 2012

For industry estimates of attach rates for load reduction:
Market opportunity for load reduction
June 6, 2012


1 Comment

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One response to “Awaiting 32GB HCDIMMs

  1. Pingback: Memory choices for the IBM System x3300 M4 | ddr3memory

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