Table 3. x3850 X5 Memory RAS Features (continued)
Nodes Hemisphere
Mode
(DIMM
configuration
match
between
both CPU
memory
controllers)
(Note 1)
Memory
Mirroring
(Note 2)
DIMM
Sparing (2
DIMMs
spare per
memory
card) (Note
3)
DDDC
Sparing (1 x4
DRAM spare
per DIMM
pair) (Note 4)
RBS Sparing
(1 x4 DRAM
spare per
DIMM pair)
(Note 5)
2 nodes (QPI
scaling)
Required for
QPI scaled
2-node.
Unmatched
memory is
discarded to
enable
Hemisphere
Mode on all
installed
CPUs
Not
supported
Not
supported
Auto enabled
for x4
memory
controlled by
Westmere-EX
CPUs.
Not
supported
2 nodes and
MXA5 (EXA
scaling)
Not required
for EXA
2-node. Auto
enabled
when
conditions
met on all
installed
CPUs; always
enabled on
MAX5.
CPU
Intrasocket
and MAX5
mirroring
enabled by
UEFI setting.
Enabled by
UEFI setting
when
conditions
met.
Unsupported
in MAX5
memory.
Auto enabled
for x4
memory
controlled by
Westmere-EX
CPUs.
Auto enabled
in MAX5
with x4
DIMMs.
Notes:
1. Hemisphere Mode
a. Both memory controllers in a CPU have the same DIMM configuration;
improves performance 16-56%.
b. UEFI automatically enables CPU Hemisphere mode when all installed CPUs
meet the requirement.
c. Memory configurations from one CPU to another need not match.
d. There is no separate UEFI Setup setting for Hemisphere mode.
e. CPU Hemisphere Mode is disabled when Memory Sparing (DIMM sparing)
or Mirroring is enabled in UEFI Setup.
f. At least 4 DIMMs per CPU are required for Hemisphere mode, but 8
DIMMs per CPU is better because it avoids a 50% performance loss.
g. Hemisphere mode is required for 8 socket QPI scaled (non EXA MAX5)
configuration (Memory Sparing/Mirroring Settings are ignored).
h. Hemisphere mode is not required in an 8 socket EXA scaled (via MAX5).
Each node would auto enable Hemisphere Mode in it's CPUs based on the
CPU memory configurations in that node alone.
i. MAX5 memory is always in Hemisphere Mode, irrespective of the CPU
Hemisphere Mode.
Chapter 2. Introduction 11