The following rules apply when selecting the memory configuration:
Server supports RDIMMs, and LRDIMMs.
Mixing different types of memory (RDIMMs and LRDIMMs) is not supported.
Mixing 1.5 V and 1.35 V DIMMs in the same server is supported; in such cases, all DIMMs operate at
1.5 V.
The maximum number of ranks supported per one channel is eight (with the exception of Load Reduced
DIMMs, where more than eight ranks are supported because one quad-rank LRDIMM provides the
same electrical load on a memory bus as a single-rank RDIMM).
The maximum quantity of DIMMs that can be installed in server depends on number of CPUs, DIMM
type, rank, and operating voltage as shown in the "Maximum quantity" row in the following table.
All DIMMs in all CPU memory channels operate at the same speed, which is determined as the lowest
value of:
The memory speed supported by the specific CPU.
The lowest of maximum operating speeds for the selected memory configuration that depends on
rated speed, operating voltage, and quantity of DIMMs per channel, as shown under "Maximum
operating speed" section in the following table.
The following table shows the characteristics of the supported DIMMs. Tables cells highlighted with a gray
background indicate when the combination of DIMM voltage and the number of DIMMs per channel still allows
the DIMMs to operate at a rated speed.
Table 5. Maximum memory speeds
DIMM
specification
RDIMM
LRDIMM
Rank
Single rank
Dual rank
Dual rank
Quad rank
Part numbers
00D5024 (4 GB)
00D5036 (8 GB)
00D5020 (4
GB)
00D5032 (8
GB)
00D5040 (8 GB)
00D5048 (16
GB)
46W0761 (32
GB)
Rated speed
1600 MHz
1866 MHz
1866 MHz
1866 MHz
1866 MHz
Rated voltage
1.35 V
1.5 V
1.5 V
1.5 V
1.5 V
Operating voltage
1.35 V
1.5 V
1.5 V
1.5 V
1.5 V
1.5 V
Max qty supported*
24
24
24
24
24
24
Max DIMM capacity
8 GB
8 GB
8 GB
8 GB
16 GB
32 GB
Max memory capacity
192 GB
192 GB
192 GB
384 GB
384 GB
768 GB
Max. memory at rated speed
None
128 GB
64 GB
64 GB
256 GB
512 GB
Maximum operating speed
1 DIMM per channel
1333
MHz
1600
MHz
1866 MHz
1866 MHz
1866 MHz
1866 MHz
2 DIMMs per channel
1333
MHz
1600
MHz
1600 MHz
1600 MHz
1866 MHz
1866 MHz
3 DIMMs per channel
800 MHz
1066
MHz
1066 MHz
1066 MHz
1066 MHz
1066 MHz
* The maximum quantity that is supported is shown for two processors installed.
The following memory protection technologies are supported:
ECC
Chipkill (for x4-based memory DIMMs)
Memory mirroring
Memory rank sparing
If memory mirroring is used, then DIMMs must be installed in pairs (a minimum of one pair per each CPU), and
both DIMMs in a pair must be identical in type and size.
System x3550 M4 (E5-2600 v2) (withdrawn product)
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