Technical information

CHAPTER 4
Expansion Features
RAM Expansion Slots 69
running—your instructions to the user should include warnings about the
possibility of data corruption.
RAM Expansion Slots 4
The computer has two RAM expansion slots that accommodate standard SO
(small outline) DIMMs using SDRAM devices. One slot is on the bottom of the
system module and is normally occupied by the factory-installed SO-DIMM.
The other slot is on the top of the system module and is available for a
user-installed SO-DIMM.
RAM expansion SO-DIMMs for the PowerBook G3 Series computer must use
SDRAM devices. If the user installs an SO-DIMM that uses EDO devices, the
failure chimes will sound when the user attempts to restart the computer and
the computer will not operate.
An SO-DIMM using presently-available parts can contain either 16, 32, 64, 128,
or 256 MB of memory. Because of space limitations, a 256 MB SO-DIMM will fit
only in the top slot.
Total RAM capacity using the highest-density devices available is 384 MB and is
limited by the space available for the SO-DIMMs. The bottom slot can
accommodate a 1.5-inch SO-DIMM with up to 128 MB of SDRAM. The top slot
can accommodate a 2.0-inch SO-DIMM with up to 256 MB of SDRAM.
Mechanical Design of RAM SO-DIMMs 4
The RAM expansion modules used in the PowerBook G3 Series computer are
standard 144-pin 8-byte DRAM SO-DIMMs, as defined in the JEDEC
specifications.
The mechanical characteristics of the RAM expansion SO-DIMM are given in
the JEDEC specification for the 144-pin 8-byte DRAM SO-DIMM. The
specification number is JEDEC MO-190; it is available from the Electronics
Industry Association’s web site, at
http://www.eia.org/jedec/download/freestd/pub95/#MO
The specification defines SO-DIMMs with nominal heights of 1.0, 1.25, 1.5, or
2.0 inches. The PowerBook G3 Series computer can accommodate two