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Memory per drawer
Each drawer features the following minimum and maximum memory ranges:
Minimum:
– 4 DIMMs per QCM x 8 QCM per drawer = 32 DIMMs per drawer
– 32 DIMMs per drawer x 8 GB per DIMM = 256 GB per drawer
Maximum:
– 16 DIMMs per QCM x 8 QCM per drawer = 128 DIMMs per drawer
– 128 DIMMs per drawer x 16 GB per DIMM = 2 TB per drawer
Memory DIMMs
Memory DIMMs include the following features:
Two SuperNOVA chips each with a bus connected directly to the processor
Two ports on the DIMM from each SuperNova
Dual CFAM interfaces from the processor to each DIMM, wired to the primary SuperNOVA
and dual chained to the secondary SuperNOVA on the DIMM
Two VPD SEEPROMs on the DIMM interfaced to the primary SuperNOVA CFAM
80 DRAM sites - 2 x 10 (x8) DRAM ranks per SuperNova Port
Water cooled jacketed design
50 watt max DIMM power
Available in sizes: 8 GB, 16 GB, and 32 GB (RPQ)
For best performance, it is recommended that all 16 DIMM slots are plugged in each node. All
DIMMs driven by a quad-chip module (QCM) must have the same size, speed, and voltage
rating.
1.4.9 Quad chip module
The previous sections provided a brief introduction to the low-level components of the Power
775 system. We now look at the system on a modular level. This section discusses the
quad-chip module or QCM, which contains four POWER7 chips that are connected in a
ceramic module.
The standard Power 775 CEC drawer contains eight QCMs. Each QCM contains four, 8-core
POWER7 processor chips and supports 16 DDR3 SuperNova buffered memory DIMMs.
Figure 1-12 on page 24 shows the POWER7 quad chip module which contains the following
characteristics:
4x POWER7 cores
32 cores (4 x 8 = 32)
948 GFLOPs / QCM
474 GOPS (Integer) / QCM
Off-chip bandwidth: 336 Gbps (peak):
– local + remote interconnect
Chapter 1. Understanding the IBM Power Systems 775 Cluster
23
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