RAM detective work

Discussion in 'Mac Accessories' started by techound1, Apr 30, 2006.

  1. techound1 macrumors 68000


    Mar 3, 2006
    Inspired by Hummer's post:

    A fistful of RAM has been dumped on me. I know some is PC and some is Mac.

    Is there a source or a process for ferreting out what the heck I have? From CanadaRAM's reply to Hummer, it sounds like starting with a pin count is in order. But where do I go from there? Some of it doesn't even seem to have numbers to google...
  2. CanadaRAM macrumors G5


    Oct 11, 2004
    On the Left Coast - Victoria BC Canada
    There are SIMMs (Single Inline Memory Modules)
    and DIMMs (Dual Inline Memory Modules - count the pins on both sides of the module)
    These two are long and rectangular, like a stick of chewing gum

    Next there are SODIMMs (Small-Outline Dual Inline Memory Module) which are shorter and more square - relatively shorter along the contact edge. These are mostly laptop RAM.

    A RAMBus RIMM (RAMBus Inline Memory Module) is a type of DIMM, but is electrically in a world of its own. Fast, for its time, but too expensive and was ousted from the market by cheaper DDR DIMMs.

    Then, classify the module by the number and placement of pins:

    30 pin SIMM - big, fat contacts, early compact Macs and Mac IIs up to the Quadra 700 - some models required banks of 4

    64 pin SIMM, special for Mac IIfx and LaserWriter IIntx, very rare

    72 pin SIMM - Mac LC. Performa, Quadra, often had to be installed in pairs, up to PowerMac 6100s Could be FPM or EDO, difficult to tell

    72 pin SODIMM - used in some IBM and Toshiba Laptops, never used in Macs

    100 pin DIMM *also called SODIMM* - printer RAM for HP laser Printers and the like

    EDO 144 pin SODIMM - used in some IBM and Toshiba Laptops, never used in Macs

    144 pin SDRAM SODIMM -- 72 per side, "laptop" RAM, could be PC66. PC100, PC133 (should be labelled): iMac G3 Tray load 233-333 MHz, most Powerbook G3, iBooks up to G3, Titanium Powerbook G4, iMac G4 700 and 800

    168 pin 5V DIMM - PowerMacs 7200 through 9600 Can be either EDO or FPM, difficult to tell unless labelled. EDO must not be used in the PM 7200. 5.25" long

    168 pin 3.3V EDO DIMM - PowerMac 4400 and Motorola Starmax Mac Clones. 5.25" long

    168 pin SDRAM DIMMs - PC66, PC100, PC133 Synchronous RAM - should be clearly labelled with the speed - 1Mac G3 250 MHz and above, G3 & some G4 machines, some USB 1.1 eMacs 700 MHz - 1 GHz 5.25" long

    184 pin DIMM - DDR DIMM, PC2700, PC3200 Mirror Disk Drive G4's, Single and Dual Processor PowerMac G5's, Mini G4, iMac G5 Rev A and B, USB 2.0 eMacs 1 GHz and up 5.25" long

    200 pin SODIMM DDR for Aluminum G4 Powerbooks (15 and 17" up to Oct 19 2005, and all 12" to date), iMac G4 1 GHz and up

    240 pin DDR2 DIMM 533 MHz - Dual-core PowerMac G5, iMac G5 iSight model

    200 pin DDR-2 SODIMMs - intel Macs 667 MHz, the Powerbook G4 HD (DL) model used 533 MHz.

    RAMBus 184 pin RDRAM RIMMs - never used in Macs.

    I have glossed over a few types here, there are several types of VRAM used in Macs, plus some proprietary modules used in early Powerbooks, and several different types of MicroDIMM used in PCs. There is also a 232 pin 32-bit RAMBus which is exceedingly rare.

    If the module has a multiple of 4 (8, 16, 32) memory chips on it, it will be a standard, non-ECC module. If it has a multiple of 3 (9, 18, 26) then it is an Error correcting (ECC or parity) module used in servers, and almost never in Macs.

    Capacity is harder to determine, if the label has no information.

    We have more definitions at http://www.canadaram.com/glossaryofterms.htm


    Attached Files:

  3. jsw Moderator emeritus


    Mar 16, 2004
    Andover, MA
    Thanks for the great detail - perhaps you would consider adding it to the guide?
  4. xsedrinam macrumors 601


    Oct 21, 2004
    Detective work, well done. Thanks is a good word.
  5. Mitthrawnuruodo Moderator emeritus


    Mar 10, 2004
    Bergen, Norway
    Nice work... maybe worthy of a Guide entry...? :)
  6. jadekitty24 macrumors 65816


    Oct 19, 2005
    The poor section of Connecticut
    Oh Mylanta™! That is unbelievably informative! I shall keep that on my computer for future reference. Thank you, CanadaRAM!:D
  7. mad jew Moderator emeritus

    mad jew

    Apr 3, 2004
    Adelaide, Australia
  8. yellow Moderator emeritus


    Oct 21, 2003
    Portland, OR
    Jeeze CanadaRAM, you'd think you worked at a RAM company or something. Talk about preachy! Sheesh! :rolleyes:
  9. baby duck monge macrumors 68000

    baby duck monge

    Feb 16, 2003
    Memphis, TN
    It never ceases to amaze me how helpful CanadaRAM can be, especially when it comes to RAM information. And he's usually so quick at getting information out to people, too!

    /tips hat
  10. annk Administrator


    Staff Member

    Apr 18, 2004
    Somewhere over the rainbow
    That was amazing, CanandaRam - hope it helped the OP. :)
  11. techound1 thread starter macrumors 68000


    Mar 3, 2006
    That was freakin' great, CanadaRAM!!! Thanks so much for the help.

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