Comparing RDIMMs, LRDIMMs and HCDIMMs/HDIMMs
UPDATE: 07/06/2012 – VMware certifies Netlist as sole memory vendor
Adding this as an entry point (or crash course) for folks asking about HCDIMMs and HDIMMs on twitter.
IBM HCDIMMs are Netlist HyperCloud.
HP HDIMMs are Netlist HyperCloud (called “HP Smart Memory HyperCloud”).
HP Smart Memory includes some other diagnostic/error features, and so that feature set has been extended to the HyperCloud and it is therefore also called a “HP Smart Memory”.
For 32GB memory modules – the problem with 32GB RDIMMs
Currently HP does not list a 32GB RDIMM in the docs (although it may still offer it).
The reason is that the 32GB RDIMM will only be available in 4-rank (4-rank).
For 16GB memory modules use at 1 DPC and 2 DPC
If the memory you need is going to require 1 DPC, or 2 DPC, you are better off buying the HP Smart Memory RDIMMs.