Memory; Overview; Dimms Supported; Dimm Slots - Dell PowerEdge R715 Technical Manual

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6 Memory

6.1 Overview

The PowerEdge R715 utilizes DDR3 memory providing a high performance, high-speed memory
interface capable of low latency response and high throughput.
Key features of the R715 memory system include:

Support for up to 256 GB of memory (16 x 16 GB RDIMMs)

Support for Registered ECC DDR3 DIMMs (RDIMM) and Unbuffered DDR3 DIMMs (UDIMM)

Support ODT (On Die Termination)

Clock gating (CKE) to conserve power when DIMMs are not accessed (DIMMs enter a low power
self-refresh mode)
2

I C access to SPD EEPROM for access to RDIMM thermal sensors

Support for Closed Loop Thermal Management on RDIMMs

Single Bit Error Correction

Multi Bit Error Detection

Support for Advanced ECC (Chipkill) Code
o SSC (Single Symbol Correcting for x4 devices)
o DSD (Double Symbol Detecting for x4 devices)

Support for Memory Sparing in limited configurations

1.5V and 1.35V LV DDR3 support

6.2 DIMMs Supported

The PowerEdge R715 supports DDR3 RDIMMs and UDIMMs. The memory interface uses 1 GB, 2 GB, 4
GB, 8 GB, and 16 GB RDIMMs and 1 GB and 2 GB UDIMMs.

6.3 DIMM Slots

The DDR3 memory interface consists of four memory channels per processor socket. Each channel
supports up to two RDIMMs for single/dual/quad rank or two UDIMMs. Population order is identified
by the silkscreen designator and the System Information Label (SIL) located on the chassis cover.
The following DIMM population rules apply:

If DIMMs of different speeds are mixed, all channels will operate at the fastest common
frequency.

If online sparing is enabled, identical DIMMs must be installed in the same slots across each
channel.

Symmetrical DIMM population is not required. Mixing of memory sizes and ranks are allowed
for flexibility.

Identical population of memory channels (same speed, size, and type) allows support for
additional features, depending on the memory population:
o Two channels per CPU:
 Performance feature CS (chipselect) memory interleaving
Online sparing with ranks of either 2R-2R or 1R-2R

o Four channels per CPU: Performance feature channel memory interleaving
o All memory channels: Performance feature node memory interleaving
PowerEdge R715 Technical Guide 28