Figure 1-8. Memory Subsystem - HP Integrity rx8640 Installation Manual

The memory subsystem comprises four independent quadrants. Each quadrant has its own memory data bus
connected from the cell controller to the two buffers for the memory quadrant. Each quadrant also has two
memory control buses: one for each buffer.
Figure 1-8 Memory Subsystem
DIMMs
The memory DIMMs used by the server are custom designed by HP. Each DIMM contains DDR-II SDRAM
memory that operates at 533 MT/s. Industry standard DIMM modules do not support the high availability
and shared memory features of the server. Therefore, industry standard DIMM modules are not supported.
The server supports DIMMs with densities of 1, 2, 4, and 8 GB. Table 1-2 on page 26 lists each supported
DIMM size, the resulting total server capacity, and the memory component density. Each DIMM is connected
to two buffer chips on the cell board.
Chapter 1
DIMM
DIMM
Address/
Buffer Controller Buffer
Buffer
DIMM
DIMM
DIMM
DIMM
Address/
Controller
Buffer Buffer
Buffer
DIMM
DIMM
Front Side Bus 1
CPU 2 CPU 3
HP Integrity rx8640 and HP 9000 rp8440 Server Overview
PDH Riser
Board
Buffer
Buffer
Front Side Bus 0
Cell
Controller
Detailed Server Description
DIMM
DIMM
Address/
Controller Buffer
Buffer
DIMM
DIMM
DIMM
DIMM
Address/
Controller
Buffer
Buffer
DIMM
DIMM
CPU 1 CPU 0
25