Release Notes

12 Memory Errors and Dell PowerEdge YX4X Server Memory RAS Features
Fault Resilient Mode (FRM)
Fault Resilient Mode Feature Support Table
Platforms Supported
Intel Platforms: 
(Xeon SP Families Only)
AMD Platforms: 
DIMMs Supported
x4 DIMMs: 
x8 DIMMs: 
Memory Configuration
Required
• Memory channels must be populated as either all one DIMM per
channel or two DIMMs per channel
FYI: Dell has published a separate technical whitepaper specifically for Fault
Resilient Mode.
Fault Resilient Mode (FRM) is a memory RAS feature that leverages partial memory mirroring to create a
fault resilient memory region specifically for hypervisors. With this feature enabled, the hypervisor will
ensure that critical memory functions only utilize the mirrored memory region. Because this memory
region is fully redundant, any fatal uncorrectable memory failures in this area that might normally crash
the system should be otherwise averted. An additional advantage of this feature is that the memory
capacity overhead for FRM only 25% compared to 50% in full memory mirroring.
In order to use this feature, VMware vSphere 5.5 or later must be installed. Also, memory channels must
be populated with all one DIMM or all two DIMMs (for example, 24 DIMM systems should have 12
DIMMs or 24 DIMMs installed). Fault Resilient Mode is disabled by default and must be enabled through
the BIOS setup menu.
Important: Consult your PowerEdge server installation and service manual for
complete memory population guidelines to properly enable Fault Resilient Mode.
Memory Self-Healing
Memory Self-Healing Feature Support Table
Platforms Supported
Intel Platforms: 
(Xeon SP Families Only)
AMD Platforms: 
DIMMs Supported
x4 DIMMs: 
x8 DIMMs: 
The Dell EMC PowerEdge server memory self-healing capability has two key components: post package
repair and memory retraining. Intel Xeon SP based platforms are capable of doing both, whereas AMD
EPYC platforms can only perform retraining (which occurs every boot as part of normal operation).
Post Package Repair (PPR) is an industry-standard capability, defined by JEDEC, where a memory module
is capable of swapping out degraded rows of memory with spare ones being held in reserve. While
JEDEC requires that all DDR4 memory be built with at least one spare row per DRAM bank group, Dell
requires all memory suppliers manufacture genuine Dell DIMMs with a significantly larger number of