eXFlash DIMM Configuration and Support Requirements - System x

Updated:  01/28/2015
Doc Version 1.3

Supported eXFlash DIMM Memory-Channel Storage

• IBM eXFlash 200GB DDR3 Storage DIMM, opt p/n 00FE00
• IBM eXFlash 400GB DDR3 Storage DIMM, opt p/n 00FE005
• eXFlash DDR3 Storage DIMM User's Guide

Supported System x Servers

The following links provide additional system specific information and software as it relates to supporting eXFlash DIMMs:

• System x3650 M4
• System x3850 X6
• System x3950 X6
• Lenovo Flex System x280 X6 / x480 X6 / x880 X6 Compute Node

IBM eXFlash DIMM Planning Considerations

• A maximum of one eXFlash DIMM per DDR3 memory channel is supported
• The operating environment is limited to 30C max ambient temperature when eXFlash DIMMs are installed
• At least one RDIMM must be installed in the same memory channel as the eXFlash DIMM(s)
• eXFlash DIMMs are compatible with RDIMMs; other memory types like LRDIMMs or UDIMMs are not supported
• eXFlash DIMMs with different capacities (that is, 200 GB and 400 GB) cannot be intermixed in the same server
• Configure the following UEFI settings before installing eXFlash DIMMs into the server:
• • System Settings | Memory | Memory Mode: Independent
  • System Settings | Memory | Memory Speed:   Max Performance
  • System Settings | Memory | Socket Interleave:  NUMA
  • System Settings | Memory | Mirroring:  Disabled
  • System Settings | Memory | Sparing:  Disabled
  • System Settings | Operating Modes | QPI Link Frequency:  Max Performance.
• The “Legacy Only” boot option within the System Settings | Boot Manager is not supported with FlashDIMMs
• Servers configured to operate in "balanced" or "low-power" modes, will lower the speed of eXFlash DIMMs to 1066 MHz
• eXFlash DIMMs do not support the following memory features configurable in the uEFI settings:  lockstep, memory mirroring, and memory sparing
• eXFlash DIMMs operated at 1600 MHz, 1333, or 1066 MHz frequencies depending on the RDIMM configuration, which may be slower than the maximum specification of the memory RDIMM's supported
  

Note:  The memory channel will operate at a frequency considering the speed of the slowest device and the overall module load distribution.  Increasing the number of modules with higher density ranks increases the total load and reduces the speed the memory can operate within margin.  The speeds for the memory channel are noted in the Memory Module Population Rules below.

Additional Resources

IBM Redbooks Product Guide for IBM eXFlash DDR3 Storage DIMMs
http://www.redbooks.ibm.com/abstracts/tips1141.html?Open

For a list of all supported options, see the IBM Redbooks Product Guide for IBM System x3650 M4 at:
http://www.redbooks.ibm.com/abstracts/tips0850.html?Open

For a list of all supported options, see the IBM Redbooks Product Guide for the IBM System x3850 X6:
http://www.redbooks.ibm.com/abstracts/tips1084.html?Open

For a list of all supported options, see the IBM Redbooks Product Guide for the IBM System x3950 X6:
http://www.redbooks.ibm.com/abstracts/tips1132.html?Open

For a list of all supported options, see the IBM Redbooks Product Guide for the Lenovo System x240 / x440 / x880 X6 Compute Node
:
http://lenovopress.com/tips1286