Specifications

Chapter 1. General description 19
1.4.7 Memory features
In POWER7 systems, DDR3 memory is used throughout. The POWER7 DDR3 memory uses
a memory architecture to provide greater bandwidth and capacity. This enables operating at a
higher data rate for large memory configurations. All processor cards have 16 memory DIMM
slots (eight per processor) running at speeds up to 1066 MHz and must be populated with
POWER7 DDR3 Memory DIMMs.
Figure 1-5 outlines the general connectivity of an 8-core POWER7 processor and DDR3
memory DIMMS. The eight memory channels (four per memory controller) can be clearly
seen.
Figure 1-5 Outline of 8-core POWER7 processor connectivity to DDR3 DIMMs - Used in a 2-socket
Power 770 and Power 780
On each processor card for the Power 770 and Power 780 there is a total of 16 DDR3
memory DIMM slots to be connected. When using two SCMs per card, eight DIMM slots are
used per processor, and when using four SCMs per card in the Power 780 server, four DIMM
slots are used per processor.
The quad-high (96 mm) DIMM cards can have an 8 GB, 16 GB, 32 GB, or 64 GB capacity
and are connected to the POWER7 processor memory controller through an advanced
memory buffer ASIC. For each DIMM, there is a corresponding memory buffer. Each memory
channel into the POWER7 memory controllers is driven at 6.4 GHz.
Each DIMM (except the 64 GB DIMM) contains DDR3 x8 DRAMs in a configuration, with 10
DRAMs per rank, and plugs into a 276-pin DIMM slot connector. The 64 GB DIMM is an
8-rank DIMM using x4 parts (1024Kx4). The x4 DIMMs are 20 DRAMs per rank.
POWER7 Processor Chip
Memory Controller 0 Memory Controller 1
L3 Cache
Core Core Core Core
Core Core Core Core
Advanced Buffer
DIMM 5
A B C D D C B A
Advanced Buffer
DIMM 8
Advanced Buffer
DIMM 7
Advanced Buffer
DIMM 6
Advanced Buffer
DIMM 4
Advanced Buffer
DIMM 3
Advanced Buffer
DIMM 2
Advanced Buffer
DIMM 1