Specifications

cell design details
The cell controller (CC) is at the heart of each cell board. The CC provides the communications
link between processors, memory, I/O, PDH (processor-dependent hardware), and the crossbar
backplane. Adjacent to the CC are up to four processors and up to 16 GB of main memory, with
future expansion up to 32 GB of memory. Each cell interfaces with the crossbar backplane at 8
GB/s of peak bandwidth, and CC-to-I/O-subsystem bandwidth is 2 GB/s peak. The cell controller
chip contains interface logic and also maintains cache coherency throughout the system.
cell configurations
An rp8400 can contain a minimum of one and a maximum of four cells. Each cell can be
purchased with two or four active PA-8700(+) processors, or with active processors in
combination with instant capacity on demand (iCOD) processors.
The rp8400 supports three processor speeds: 650 MHz, 750 MHz, and 875 MHz. The ability to
mix processor speeds within a chassis is supported (but processors within a cell or partition must
be of the same speed). The ability to mix processor speeds provides enhanced investment
protection by allowing you to add the latest available processor technology to an existing
installation.
figure 8. An rp8400 cell supports up to four processors and up to 16 GB of memory, with future
expansion to 32 GB.
The minimum cell configuration includes two active CPUs and 1 GB of memory per cell board.
The maximum configuration includes four active CPUs and 16 GB of memory per cell board.
Memory DIMM modules for the rp8400 are sold in sets of four (quads), with DIMM sizes of
256 MB, 512 MB, and 1 GB available. Memory quads of different sizes can be mixed within
a chassis and within a cell. However, for optimum memory interleaving and performance, it is
recommended that one memory size be selected and distributed evenly across available cells.
Within a cell the CC-to-memory peak bandwidth is 4 GB/s. Memory is accessed directly through
the CC; therefore, all memory slots are accessed regardless of the number of processors in the
cell.
cell hot-plug The HP Server rp8400 supports cell hot-plug. Coupled with the server’s partitioning capability*,
cell hot-plug allows for the servicing of cell boards within a single partition while the other
partition continues normal operation. Any number of configuration changes can be made to the
partition being serviced, including replacing the complete cell board, adding or deleting CPUs
and memory, or even increasing or decreasing the number of cells in that partition. (Cell hot-plug
is supported only in systems with two partitions.)
*
The rp8400 can be configured as a single large SMP server, or hardware-partitioned into two smaller logical servers. See “nPartitions” on page 25 for
more details about partitioning.
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