170 Chapter 9
mem3000
V2500 memory configurations
V2500 memory configurations
In the V2500 server, Excalibur Pluggable Memory Boards (EPMBs) are
installed in 16 DIMM connectors on the EWMBs.
A V2500 memory board is organized by quadrants, rows, and buses.
Each memory board has four quadrants, four rows and eight buses.
The following terms are used to describe a V2500 memory board, as
shown in Figure 39:
Slot The physical location into which DIMMs are installed.
There are 16 DIMM slots, each with a unique
designator which denotes the slot’s quadrant and bus.
Quadrant A group of four DIMM slots staggered across the
memory board.
Buses Eight buses span the four rows. Each DIMM in a
quadrant is on a different bus.
Rows Each DIMM has SDRAMs on each side and represents
two rows. For instance, the first DIMM installed in the
system would represent row 0 bus 0 and row 1 bus 0.
All DIMMs have the same SDRAMs on both sides.
Therefore, rows 0 and 1 will have the same SDRAM
size. Rows 2 and 3 will have the same SDRAM size.
Bus interleaving can be configured to either 4 way or 8
way bus interleaving. 8 way provides the best
performance. To achieve 8 way bus interleaving, all
buses on a row must be populated with DIMMs having
the same SDRAM size.
Table 70 shows the correlation between a DIMM slot and a row bus
intersection. The first DIMM to be installed in a memory board, Q0B0,
occupies row 0 bus 0 and row 1 bus 0 in quadrant 0.
