HP rp8420, Overview, Page: 6 / 22

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Memory Configuration
Memory Configuration Memory Configuration
Memory Configuration The memory DIMMs used in the HP 9000 rp8420 Server is sold in quads and is custom designed by HP.
Each DIMM contains 36×4 SDRAM memory chips qualified to run at 125 MHz, with full ECC
protection. DIMM sizes of 512 MB, 1 GB, 2 GB, and 4 GB are supported. HP 9000 rp8400 memory
modules can be carried forward to the rp8420 server. Each HP 9000 rp8420 Server cell board supports
up to 16 DIMM slots and 16 GB/s of peak memory bandwidth. The 16 GB memory modules (4×4GB
DIMMs) cannot be mixed with other memory DIMM sizes. When purchased from the factory, any given
partition can ordered with 4 GB DIMMs or non stacked DIMMs (512 MB, 1 GB or 2 GB), but not both.
When field integrated, cell boards can contain 4 GB DIMMs or non stacked DIMMs (512 MB, 1 GB or 2
GB), but not both.
HP 9000 rp8420 Server Memory DIMMs HP 9000 rp8420 Server Memory DIMMs HP 9000 rp8420 Server Memory DIMMs HP 9000 rp8420 Server Memory DIMMs
Quad Size Quad Size Quad Size Quad Size (product) rp8420 Product Number rp8420 Product Number rp8420 Product Number rp8420 Product Number rp8400 Product rp8400 Product rp8400 Product rp8400 Product
Numbers that are
Numbers that are Numbers that are Numbers that are
supported
supported supported supported
HP 9000 rp8420 Server HP 9000 rp8420 Server HP 9000 rp8420 Server HP 9000 rp8420 Server
Maximum Capacity Using 1 DIMM
Maximum Capacity Using 1 DIMM Maximum Capacity Using 1 DIMM Maximum Capacity Using 1 DIMM
Size
Size Size Size
DIMM Size DIMM Size DIMM Size DIMM Size
2 GB AB307A A6097A 32 GB 512 MB
4 GB AB308A A6098A 64 GB 1024 MB
8 GB AB309A A6100A 128 GB 2048 MB
16 GB AB322A - 256 GB 4096 MB
Memory Loading Rules Memory Loading Rules Memory Loading Rules Memory Loading Rules Memory must be installed in quads (4 DIMMs of equal density)
Memory is available in four densities: 2 GB (4×512MB), 4 GB (4×1024MB), 8 GB
(4×2048MB), and 16-GB (4 x 4096MB)
Minimum memory is 2-GB per cell
Maximum memory per system is 256 GB-using sixteen 16 GB Quads.
On each cell board, Memory Quads must be installed in the following order:
1
st
(0A, 0B, 1A, 1B), 2
nd
(2A, 2B, 3A, 3B), 3
rd
(4A, 4B, 5A, 5B), 4
th
(6A, 6B, 7A, 7B)
Performance Tuning Performance Tuning Performance Tuning Performance Tuning
Guidelines
Guidelines Guidelines Guidelines
For best performance, a cell should be configured with a multiple of 8 DIMMs or two quads
(although the server will execute properly with an odd number of quads. It takes 8 DIMMs to
populate both buses. Populating only one of the two memory buses on a cell board will deliver
only half the peak memory bandwidth.
Load memory equally across the available cell boards.
If growth is planned for the system, then plan on configuring high density 4, 8-GB, or 16-GB
modules to minimize future memory slot constraints.
Memory Latencies Memory Latencies Memory Latencies Memory Latencies There are two types of memory latencies within the HP 9000 rp8420 Server:
Memory latency within within within within the cell refers to the case where an application either runs on a partition
that consists of a single cell or uses cell local memory.
Memory latency between
between between between cell refers to the case where the partition consists of two or more cell
and cell interleaved memory is used. For example, for an rp8420 Server with four cells in the
partition, 25% of the addresses are to memory on the same cell as the requesting processor, and
the other 75% of the addresses are to memory on the other three cells.
The HP 9000 rp8420 Server memory latency depends on the number of processor modules in the
partition. Assuming that memory accesses are equally distributed across all cell boards and memory
controllers within the partition, the average idle memory latency (load-to-use) is as shown below:
QuickSpecs
HP 9000 rp8420 Server HP 9000 rp8420 Server HP 9000 rp8420 Server HP 9000 rp8420 Server
Configuration
DA - 11894 Worldwide — Version 25 — March 1, 2007 Page 6