IBM 88Y7429, x3759 M4 manual Table highlighting, Rdimm Lrdimm

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 red text indicate that the IBM System x3750 M4 supports higher memory 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				RDIMM				LRDIMM
Ranks	Single-rank DIMMs				Dual-rank DIMMs		Quad-rank LRDIMMs
Part numbers	49Y1406 (4 GB)		49Y1559	49Y1397 (8 GB)		90Y3109 (8 GB)	49Y1567 (16 GB)
			(4 GB)	49Y1563 (16 GB)		00D4968 (16 GB)	90Y3105 (32 GB)
Rated speed	1333 MHz		1600 MHz	1333 MHz		1600 MHz		1333 MHz
Rated voltage	1.35 V		1.5 V	1.35 V		1.5 V		1.35 V
Operating voltage	1.35 V	1.5 V	1.5 V	1.35 V	1.5 V	1.5 V	1.35 V		1.5 V
Max. qty supported*	48	48	48	48	48	48	48		48
Max. DIMM capacity	4 GB	4 GB	4 GB	16 GB	16 GB	16 GB	32 GB		32 GB
Max. mem. capacity	192 GB	192 GB	192 GB	768 GB	768 GB	768 GB	1.5 TB		1.5 TB
Max memory at	128 GB	128 GB	128 GB	512 GB	768 GB	512 GB	1.5	TB	1.5 TB
maximum speed
Max operating speed (MHz)
1 DIMM per channel	1333 MHz	1333 MHz	1600 MHz	1333 MHz	1333 MHz	1600 MHz	1333	MHz	1333 MHz
2 DIMMs per channel	1333 MHz	1333 MHz	1600 MHz	1333 MHz	1333 MHz	1600 MHz	1333	MHz	1333 MHz
3 DIMMs per channel	1066 MHz	1066 MHz	1066 MHz	1066 MHz	1333 MHz	1333 MHz	1333	MHz	1333 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 11