Dell PowerEdge: R610 / R710 only detect my 1333MHZ DDR3 RAM as 1067MHZ in System BIOS

Nowadays server already using DDR3 Memory in most of the platform regardless it is Dell, IBM or HP. For this new technology, it have two types: Registered (RDIMM) & Unbuffered (UDIMM) ECC DDR3.

The primary differences between UDIMMs and RDIMMs are:

• RDIMMs have a register used as a pass through for address and command signals. This allows servers to support more RDIMMs per channel than UDIMMs.
• RDIMMs consume more power than UDIMMs but are available in larger capacities and higher ranks.
• RDIMMs also provide additional data protection and reliability features.

(Reference: Memory Selection Guidelines for High Performance Computing with Dell™ PowerEdge™ 11G Servers)

I'm not going to go into detail of the difference of RDIMM & UDIMM, but I would like to share the situation below:

Customer contact me and request my explanation about why new server's motherboard is faulty. Then he share me the screen from System BIOS, that all 1333Mhz Memory are detected as 1067Mhz only.

I checked the Intel Processor that he ordered (Intel Xeon E5520 2.26Ghz), then I get the answer.

This is nothing about the motherboard, or the design of Dell platform, but this is due to the Limitation of Intel Xeon Processor.

Whitepaper (Page.11)

From the chat above, it is clearly stated that only X5550 and above able to support/detect 1333Mhz of DDR3 RAM (but still depends on processor model, DIMM speed, and DIMM population).

I hope my sharing over here can avoid further misunderstanding towards Dell platform. :-)