About Memory Modules - Sun Microsystems Fire V890 Service Manual

About Memory Modules

The Sun Fire V890 server uses 3.3-volt, 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 512-Mbyte and 1-Gbyte capacities.
Each CPU/Memory board contains slots for 16 DIMMs, 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 Sun Fire V890
CPU/Memory board. Every fourth slot belongs to the same DIMM group. The four
groups are designated A0, A1, B0, and B1.
B 1
B 0
A 1
A 0
B 1
B 0
A 1
A 0
B 1
B 0
A 1
A 0
B 1
B 0
A 0 A 1
You must physically remove a CPU/Memory board from the system before you can
install or remove DIMMs. The DIMMs must be added four at a time within the same
DIMM group and be identical—that is, all DIMMs must be from the same
manufacturing vendor and must have the same capacity (for example, four 512-
Mbyte DIMMs, four 1-Gbyte DIMMs, or four 2-Gbyte DIMMs).
Chapter 7 Hardware Configuration 221