In the M610 BIOS 1.2.7 Dell describes a change in handling more than one DIMM per channel on 1333Mhz.

Quote: "Added support for 2 Memory DIMMs Per channel when Memory Bus speed is at 1333MHz"

Question: What does that mean and how it works regarding the information above about the DIMM Count?

Kind regards
Arne

That means that you can use two DIMMs per memory channel (there are three memory channels per CPU socket and two DIMM slots per channel on the M610) at a memory bus speed of 1333Mhz. Previously you could only have one DIMM per channel if you wanted them to run at 1333Mhz (if the module was single or dual rank, quad rank drops it to 1066MHz). Not sure if any of the rank rules has changed.

See the table at the bottom of page 7:
http://www.dell.com/downloads/global/products/pedge/en/server-poweredge-11g-white-paper.pdf