To Next Page

To Previous Page

Chapter 2. Architecture and technical overview 55

2.3.4 Memory throughput

POWER7+ has exceptional cache, memory, and interconnect bandwidths. Table 2-7 shows

the bandwidth estimate for the Power 770 system running at 3.8 GHz.

Table 2-7 Power 770 memory bandwidth estimates for POWER7+ cores running at 3.8 GHz

With an increase in frequency, the Power 780 running at 4.42 GHz generates higher cache

bandwidth (Table 2-8).

Table 2-8 Power 780 memory bandwidth estimates for POWER7+ cores running at 4.42 GHz

2.3.5 Active Memory Mirroring

Power 770 and Power 780 servers have the ability to provide mirroring of the hypervisor

code across multiple memory DIMMs. If a DIMM that contains the hypervisor code develops

an uncorrectable error, its mirrored partner will enable the system to continue to operate

uninterrupted.

Active Memory Mirroring (AMM) is included with all Power 780 systems at no additional

charge. It can be enabled, disabled, or re-enabled depending on the user’s requirements.

On the Power 770, AMM is optional and must be ordered using feature code 4797. It can be

enabled, disabled, or re-enabled depending on the user's requirements.

The hypervisor code, which resides on the initial DIMMs (J1A to J8A), will be mirrored on the

same group of DIMMs to allow for more usable memory. Table 2-3 on page 51 shows the

DIMMs involved on the memory mirroring operation.

Memory Bandwidth

L1 (data) cache 182.78 GBps

L2 cache 182.78 GBps

L3 cache 121.85 GBps

System memory:

4x enclosures:

68.22 GBps per socket

1091.58 GBps

Inter-node buses (four enclosures) 158.02 GBps

Intra-node buses (four enclosures) 1075.2 GBps

Memory Bandwidth

L1 (data) cache 212.35 GBps

L2 cache 212.35GBps

L3 cache 141.56 GBps