Dell
PowerEdge M910 Technical Guide
26
7
Memory
7.1
Overview
The Dell™ PowerEdge™ M910 uses DDR3 memory providing a high-performance, high-speed memory
interface capable of low-latency response and high throughput. The M910 supports Registered ECC
DDR3 DIMMs (RDIMM) only. Each DDR3 DIMM is driven by the Intel
®
7500 Scalable Memory Buffer
(SMB)
. A memory buffer has two DDR3 channels. Each of these channels can support up to 2 DIMMs
running at 1067 MHz (or slower) speeds.
The Intel 7500 SMB supports single-, dual-, and quad-rank DIMMs. Up to four 2 GB, 4 GB, 8 GB, and
16 GB RDIMMs are supported per channel, for a total of up to 512 GB. Across processors, DIMM
populations can be different on the memory for each processor as long as the population rules for
each processor socket are followed. Additionally, all processor sockets operate in the same RAS mode
and are set up with the same memory timing parameters.
4-socket platform capability (32 DIMMs):
Up to 8 DDR3 DIMMs per socket through use of up to four Scalable Memory Buffers
Support for up to 16 GB DDR3 DIMMs
Maximum of 512 GB with 16 GB DIMMs
Memory types supported:
1066 MHz DDR3 (800 MHz and 1333 MHz availability depends on OEM validation)
Registered DIMM (RDIMM)
Single-rank (SR), dual-rank (DR), quad-rank (QR)
Actual system memory speed depends on specific processor capabilities:
6.4 GT/s SMI link speed capable of running memory speeds up to 1066 MHz
5.86 GT/s SMI link speed capable of running memory speeds up to 978 MHz
4.8 GT/s SMI link speed capable of running memory speeds up to 800 MHz
7.2
DIMMs Supported
If DIMMs of different speeds are mixed, all channels operate at the fastest common frequency.
UDIMMs are not supported. The first DIMM slot in each channel is color
‐
coded with white ejection
tabs for ease of identification.
The M910’s DIMM sockets are placed 0.40‖ apart, center
‐
to
‐
center, to provide enough space for
sufficient airflow to cool stacked DIMMs. DIMMs must be installed in each channel starting with the
DIMM farthest from the processor (DIMM 1). Population order is identified by silkscreen and a label.
The order is dependent on the memory configuration used.
7.3
DIMM Slots
For information, see the
System Memory
section in the Installing Blade Components chapter of the
Dell PowerEdge Modular Systems Hardware Owner’s Manual
on
Support.Dell.com/Manuals
.
7.4
Intel 7500 Scalable Memory Buffer (SMB)
The Intel 7500 SMB supports one Intel Scalable Memory Interconnect (Intel SMI), two DDR3 channels,
and one SMBus slave interface at 100 KHz. It does not support the repeater functionality. Target
package size is 19.5 mm x 24.5 mm with 0.8 mm pitch. Intel SMI supports link speeds of 4.8 GT/s,
