Memory Subsystem; Cooling Subsystem - Oracle X5-4 Service Manual

Server Subsystems Overview

Memory Subsystem

This section describes the server memory subsystem.
For more information about system memory (including DIMM population rules) and MR cards,
see: "Memory Riser Card and DIMM Reference" on page 154
Memory Slot Capacity
System memory resides on memory riser (MR) cards. Each card has 12 DIMM slots. The slot
capacity of the server depends on the number of MR cards in the server, which in turn depends
on the number of CPUs in the server. The server is available in a two CPU configuration
and a four CPU configuration. Each CPU requires two MR cards. Therefore, a two-CPU
configuration has 48 slots (four MR cards) and a four-CPU configuration has 96 slots (eight
MR cards).
Memory Channels and Buffers
MR cards contain twelve DIMM slots, four DDR3 channels, and two memory buffer ASICs.
Each memory buffer has two channels (A and B) and links to three DIMM slots per channel.
Each memory buffer is connected to the processor's built-in memory controller by an SMI-2
link.
Memory Performance
For balanced performance, each channel for each memory buffer on the MR card must be
populated. The only exception supported is a minimum factory configuration of two 16 GB
DIMMs per MR card in DIMM slots D0 and D3.

Cooling Subsystem

The internal components in the system are cooled by air that is pulled in through the front of the
server and exhausted out the back of the server. Cooling occurs in two areas of the chassis, the
power supply area and the motherboard area.
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