Sun Microsystems Sun Blade 1000 Service Manual page 286

Note – DIMM capacities can differ from one group to the next. For example, four
128-Mbyte DIMMs can be installed in group 0 and four 256-Mbyte DIMMs can be
installed in group 1, but workstation performance may be impacted (see "System
Memory Interleaving" below).
Caution – DIMMs are made of electronic components that are extremely sensitive
to static electricity. Static from your clothes or work environment can destroy the
modules. Do not remove any DIMM from its antistatic packaging until you are ready
to install it on the system board. Handle the modules only by their edges. Do not
touch the components or any metal parts. Always wear a grounding strap when you
handle the modules.
C.1.3.5 System Memory Interleaving
System memory supports interleaving on 64-byte boundaries. The Sun Blade 1000
and Sun Blade 2000 system supports from one to four logical banks. For interleaving
purposes, all banks are treated identically regardless of their physical location. Two
successive accesses to distinct logical banks located in the same group of DIMMs are
processed the same as accesses to logical banks that are in separate groups of
DIMMs.
The memory controller for the Sun Blade 1000 and Sun Blade 2000 workstation
supports one way, 2-way and 4-way interleaving.
System memory is accessed only on 64-byte block reads or writes. The interleaving is
based on a 64-byte addressing and the four low-order bits of a block physical
address (PA[9:6]) determines the bank within a memory segment. The stride on
which banks are interleaved is 64 bytes (no interleaving), 128 bytes (2-way
interleaving), 256 bytes (4-way interleaving).
In only one configuration is it possible to interleave by four. To interleave by four all
groups must be populated with DIMMs of the same size.
CPU processing rate is slowed by memory module response time, and limited by the
word size (64 bytes) of its read or write requests. The word size of these read/write
requests are referred to as the processing stride.
System memory interleaving is a technique to increase CPU throughput by splitting
the system memory into independent banks that answer CPU read or write requests
independently and in parallel.
The group addresses for the Sun Blade 1000 and Sun Blade 2000 are listed in the
following table.
C-14 Sun Blade 1000 and Sun Blade 2000 Service Manual • January 2002