About Memory Modules - Sun Microsystems Sun Fire V480 Parts Installation And Removal Manual

About Memory Modules

The Sun Fire V480 server uses 3.3V, high-capacity dual inline memory modules
(DIMMs). The DIMMs are built with synchronous dynamic random access memory
(SDRAM) chips that operate at a 75-MHz clock frequency. The system supports
DIMMs with the following capacities:
256 Mbytes
512 Mbytes
1 Gbyte
Support for larger capacity DIMMs may be offered as they become available.
Each CPU/Memory board contains slots for 16 DIMMs. Total system memory ranges
from a minimum of 2 Gbytes (one CPU/Memory board with eight 256-Mbyte
DIMMs) to a maximum of 32 Gbytes (two CPU/Memory boards fully populated
with 1-Gbyte DIMMs).
Within each CPU/Memory board, the 16 DIMM slots are organized into groups of
four. The system reads from, or writes to, all four DIMMs in a group simultaneously.
DIMMs, therefore, must be added in sets of four.
The figure below shows the DIMM slots and DIMM groups on a CPU/Memory
board. Every fourth slot belongs to the same DIMM group. The four groups are
designated A0, A1, B0, and B1.
Chapter 4 Servicing the CPU/Memory Board and Related Components 79