DDR RAM vs SD RAM or what ever it is

Discussion in 'Buying Tips, Advice and Discussion (archive)' started by Solafaa, Nov 14, 2004.

  1. Solafaa macrumors 6502a


    Jul 15, 2004
    Daddy said not to talk to strangers
    Whats the diffrence and what is better?

    My friend is looking into buying extra RAM for his G4 PowerMac and he dose not know what kind of RAM he wants.
  2. brap macrumors 68000

    May 10, 2004
    It's not a choice. They are different sizes and specifications. DDR is faster, and newer. Get him to look his system up at everymac.com.
  3. TLRedhawke macrumors 6502

    Sep 17, 2004
    As stated, yes, no system will take both SD and DDR, it's one or the other. However, for a G4 PowerMac, I happen to know offhand which ones they take. If the machine is a "Graphite" one (I think they look blue, but Apple insists on calling them graphite), that is, running from 300MHz to 800MHz (I think), then it takes SDRAM (PC133). If the machine is a quicksilver, with the single 867MHz processor, then it also takes SDRAM. If it is any other quicksilver, or later, it takes DDR (PC2100).
  4. Mechcozmo macrumors 603


    Jul 17, 2004
    DDR- Double Data Rate. Not backwards compatible with normal PC133, PC100 or PC66 RAM.

    PC***- the asterisks refer to the speed of the RAM. PC133 would work in a PC100 system, but at the lower speed.

    DDR266, DDR333, and DDR400 are the main varieties of DDR RAM out today. DDR400 would work in a DDR333 or 266 (or other) system but at the lower speed.

    If you place a stick of RAM with a lower speed into a computer that can accept the high speeds, you limit the bus to that speed RAM. So it is OK to go above the speed RAM your computer can take but not below.

    SO-DIMM- Small Outline RAM. Can be DDR or not, just means it is smaller.

    SIMM- Single Integrated Memory Module. Used years ago, now everything is a DIMM. I am just telling you about SIMMs so that you know what they are.

    DIMM- Double Integrated Memory Module. Used today.

    Your friend's Mac will use DIMMs, but I do not know about DDR... most likely not. Every Mac.com has information on what RAM speeds the computer will take.

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