HolidayBuyer's Guide

512MB SDRAM in PowerBook G4 and iBook: a follow-up

512MB SDRAM in PowerBook G4 and iBook: a follow-up

Several readers have provided additional information (also see previous) on using 512MB SDRAM in a G4 PowerBook and iBook (Dual USB):

    PowerBook G4 memory The RAM upgrade notes on the Apple - Support - PowerBook Web page clearly denotes acceptable specifications:

    • Small Outline-Dual Inline Memory Module (SO-DIMM) format
    • 38.1 mm or 1.5 inch height or shorter
    • 64 MB, 128 MB, 256 MB, or 512 MB
    • 144-pin
    • PC-100 Type RAM

    Note: SDRAM from an earlier PowerBook that meets these specifications can be used with your PowerBook.

    The maximum amount of RAM you can install in your PowerBook is 1 GB, using 512 MB DIMMs in both the upper and lower RAM slots. (Thanks, Bob O'Driscoll).

    iBook (Dual USB) Barry Sharp sent us these observations:

    • The new iBook's RAM expansion slot accommodates a standard SO-DIMM using SDRAM devices.
    • This SO-DIMM can be in a size of 32, 64, 128, 256, or 512 MB.
    • The RAM expansion slot can handle SO-DIMMs up to 1.25 inches in height.
    • The SO-DIMM standard defines nominal heights of 1, 1.25, 1.5, or 2.0 inches.
    • The new iBook therefore can use ONLY the 1.0 and 1.25 inch high SO-DIMMs.

    He writes: "The new iBook can accommodate an SO-DIMM no thicker than 3.8 mm (or 0.1496063 inches). Anything thicker than this will cause difficulty in replacing/aligning the Airport card and/or the keyboard. The iBook developers note states explicitly that RAM modules that exceed the specified thickness can cause reliability problems. The difficulty at this time is finding a 512 MB memory module that meets Apple's specs. I called MemoryToGo about their advertised iBook 512MB RAM module and was told:

      They don't have it in stock. They have sold some earlier and some have been returned because they don't fit! When asked about the height and thickness I was told the height was 1.0 inch and that the thickness was not known but they thought the one they had been selling was about 1/16-inch too thick. They finally told me that they believe there aren't any 512MB modules available anywhere that meet the new iBook's specs.