IBM System x3750 M4 Product Manual page 11

The following rules apply when selecting the memory configuration:
The server supports RDIMMs and LRDIMMs. UDIMMs are not supported.

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 a case, all DIMMs operate at

1.5 V.
The maximum number of ranks 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 the server depends on the number of

processors installed. The table shows the maximum when all four processors are installed. When two
processors are installed, the maximum quantity supported is a half of the quantity that is shown.
All DIMMs in the server operate at the same speed, which is determined as the lowest value of:

Memory speed that is supported by the specific processor.

Lowest of maximum operating speeds for selected memory configuration that depends on rated

speed, operating voltage, and quantity of DIMMs per channel, as shown under "Max. operating
speed" section in the table.
Table highlighting:
The entries highlighted in

frequencies than the Intel processor specification. In some instances, this configuration also results
larger memory capacity that the specification recommends.
Tables cells highlighted with a grey background indicate when the specific combination of DIMM

voltage and number of DIMMs per channel still allows the DIMMs to operate at rated speed
Table 4. Maximum memory speeds
DIMM specification
Ranks
Part numbers
Rated speed
Rated voltage
Operating voltage 1.35 V
Max. qty supported*
Max. DIMM capacity
Max. mem. capacity
192 GB
Max memory at 128 GB
maximum speed
Max operating speed (MHz)
1 DIMM per channel 1333 MHz 1333 MHz 1600 MHz 1333 MHz
2 DIMMs per channel 1333 MHz 1333 MHz 1600 MHz 1333 MHz
3 DIMMs per channel
1066 MHz
* Maximum quantity supported is shown for four processors installed. When two processors are installed, the
maximum quantity supported is a half of the quantity that is shown. When one processor is installed, the quantity is
one quarter of that shown.
IBM System x3750 M4
indicate that the IBM System x3750 M4 supports higher memory
red text
Single-rank DIMMs
49Y1406 (4 GB) 49Y1559
(4 GB)
1333 MHz 1600 MHz
1.35 V 1.5 V
1.5 V 1.5 V
48 48
48
4 GB 4 GB 4 GB
192 GB 192 GB
128 GB 128 GB
1066 MHz 1066 MHz
RDIMM
Dual-rank DIMMs
49Y1397 (8 GB) 90Y3109 (8 GB)
49Y1563 (16 GB) 00D4968 (16 GB)
1333 MHz
1.35 V
1.35 V 1.5 V
48
48
16 GB 16 GB
768 GB
768 GB
512 GB
768 GB
1333 MHz
1333 MHz
1066 MHz 1333 MHz
LRDIMM
Quad-rank LRDIMMs
49Y1567 (16 GB)
90Y3105 (32 GB)
1600 MHz 1333 MHz
1.5 V 1.35 V
1.5 V 1.35 V
48 48
16 GB 32 GB
768 GB 1.5 TB
512 GB
1.5 TB
1600 MHz 1333 MHz
1333 MHz
1600 MHz 1333 MHz
1333 MHz
1333 MHz 1333 MHz 1333 MHz
1.5 V
48
32 GB
1.5 TB
1.5 TB
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