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Note: The PowerBook G4 17-inch computer does not use memory interleaving, so installing two SO-DIMMs
of the same size does not result in any performance gain.
Address Multiplexing
Signals A[0] – A[12] and BA[0] – BA[1] on each RAM SO-DIMM make up a 15-bit multiplexed address bus that
can support several different types of DDR SDRAM devices. Table 4-2 (page 56) lists the types of devices that
can be used in the PowerBook G4 17-inch computer by size, configuration, and sizes of row, column, and
bank addresses.
Important: The PowerBook G4 17-inch computer supports only the types of DDR SDRAM devices specified
in Table 4-2 (page 56). Other types of devices should not be used with this computer.
Table 4-2 Types of DRAM devices
Column address bitsRow address bitsDevice configuration (bytes x bits x banks)Device size
10124 M x 8 x 4128 Mbits
9122 M x 16 x 4128 Mbits
8121 M x 32 x 4128 Mbits
10138 M x 8 x 4256 Mbits
9134 M x 16 x 4256 Mbits
111316 M x 8x 4512 Mbits
RAM SO-DIMM Electrical Limits
Each RAM SO-DIMM must not exceed the following maximum current limits on the 2.5 V supply:
Active: 1.2 A (8 devices at 150 mA each)
Sleep: 6 mA/128 MB
Important: The restriction on sleep current is required not only to maximize the battery life but to meet the
limitations of the backup battery during sleep swapping of the main battery. Developers of RAM expansion
modules that exceed the limit on sleep currentmust include a warning to the user that battery sleep swapping
may not work with those modules installed.
The Intrepid memory controller does not support 4-bit-wide SDRAM devices in any RAM expansion module.
56
RAM Expansion Slots
Legacy Document | 2003-03-01 | © 2003 Apple Computer, Inc. All Rights Reserved.
CHAPTER 4
Expansion Features