Infographic – memory buying guide for Romley 2-socket servers

For servers based on the Intel plan of record

UPDATE: 06/30/2012: v1.21 – added 1333MHz/1600MHz speed info
UPDATE: 06/30/2012: v1.21_ibmsys_1_0 – IBM System x memory
UPDATE: 07/01/2012: v1.21_ibmsys_1_1 – IBM System x memory
UPDATE: 07/06/2012 – non-viability of LRDIMMs
UPDATE: 07/06/2012 – viability of HyperCloud

Here is a graphical illustration of how to choose memory for 2-socket Romley servers.

Financial institutions retreat from Romley LRDIMM story

Deleted this post.

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”

On the need to qualify HyperCloud on more servers

Qualifications on other servers in the works

HyperCloud is only available on the HP DL360p and DL380p and IBM x3650 M4 servers – these are high volume virtualization/data center servers and should provide sufficient unit volume demand for Netlist.

While this volume maybe sufficient for Netlist, the lack of availability on other IBM/HP servers does create problems for end-users trying to create a mental map of “how to choose memory” for servers.

Where are the 1600MHz LRDIMMs/HyperCloud for Romley ?

Load reduction and rank multiplication at 1600MHz ?

1600MHz-rated 16GB RDIMMs (2-rank) are available for Romley – why not LRDIMM/HyperCloud ?

The reason maybe that load reduction and rank multiplication manufacturers are already outperforming the RDIMMs by ONE speed grade.

Offering a 1600MHz version that offers a FURTHER speed grade advantage, while advantageous to end-users, may not offer a greater-units-sold advantage to the manufacturers of load reduction and rank multiplication solutions.

Memory buying guide – when to use RDIMMs on Romley ?

“above 256GB requires HyperCloud” is a universal limit

256GB seems to be a magical number.

Below that feel free to use RDIMMs.

DDP vs. monolithic memory packages and their impact

32GB RDIMMs/LRDIMMs vs. 32GB HyperCloud

Both 32GB RDIMMs and 32GB LRDIMMs being offered today are using 4Gbit x 2 DDP memory packages.

32GB HyperCloud are using 4Gbit monolithic memory packages.

Is HyperCloud vs. LRDIMMs similar to Betamax vs VHS ?

Betamax vs VHS all over again ?

The choice of load reduction and rank multiplication memory – whether HyperCloud or LRDIMMs – may seem superficially like another such “standards battle” – that of Betamax vs. VHS (where the inferior technology won out because of market conditions).

This may superficially seem to be the situation with memory choices – but it is not.

Is Montage another MetaRAM ?

Intel Capital invests again

UPDATE: 07/06/2012 – non-viability of LRDIMMs
UPDATE: 07/06/2012 – now a Montage 1333MHz version like Inphi

One memory module maker makes a departure from usual practice (a memory module maker usually picks ONE of the buffer chipset suppliers in order to minimize SKUs) by producing LRDIMMs based on BOTH an Inphi LRDIMM buffer chipset, as well as one from Montage.

This might be indicative of a perception at the memory module markers of higher risk associated with LRDIMMs/Inphi.

The Montage-based LRDIMMs however seem to underperform even the Inphi-based LRDIMMs.

Non-viability of 32GB RDIMMs

The primacy of load reduction and rank multiplication for 32GB

UPDATE: added 07/06/2012: Netlist on 8Gbit DRAM die non-availability
UPDATE: added 07/06/2012: Inphi on 8Gbit DRAM die non-availability

32GB RDIMMs are all 4-rank (quad-rank).

4-rank creates a high memory load on the memory bus.