"Normal" memory in Mac Pro?

Discussion in 'Mac Pro' started by marekkurlmann, Dec 8, 2008.

  1. marekkurlmann macrumors regular

    Mar 6, 2007
    I'll likely be buying a Mac Pro in the next few weeks. I've been looking at memory to add to the system, and I always see special Mac Pro memory systems and packaging--they're at OWC, NewEgg, everywhere. Kingston and Crucial sell regular DDR2 PC2 6400 RAM and then they also sell special Mac kits.

    See this Kingston "normal" RAM, which I'd like to buy, based on price (cca. $25) and specs:

    And compare it to these "Apple compatible" RAM, priced at least twice as high:

    I plan on maxing out the RAM slots at 16 GB (2GB x 8), so price will definitely be an issue.

    According to the blurb of text on the Apple Store's ordering page for the Mac Pro, the only exceptional thing about required RAM is that:
    Apple created a more robust thermal specification for the Mac Pro FB-DIMM heat sinks that provide more efficient cooling than many other FB-DIMMs. These FB-DIMMs require less airflow to stay cool and allow the internal fans to spin at slower speeds, improving system acoustics. FB-DIMMs made by other manufacturers that do not include a sufficient heat sink may cause the fans to run faster (and louder) or the memory chips to run slower so as not to overheat.

    So basic question: Why can't I just buy "normal" RAM with a heat spreader and pop it into my Mac Pro? What's the downside?

    Would you advise for or against buying this RAM specifically?

    Thanks a lot!
  2. hatehereyes macrumors 6502a


    Oct 18, 2008
    Moreno Valley, Ca
    The normal ddr2 memory ram will not physically fit into the mac pro memory riser cards.
    trust me i've been there already.

    Sure ddr2 and ddr2 FB-DIMMS have the same amount of pins (240) but the keys on them are slightly different.
    you will just do more damage to the computer than good.

    actually you won't be doing any good to it.
  3. goMac macrumors 603

    Apr 15, 2004
    The RAM doesn't have to be "Apple compatible", but it must be a FB-DDR2 DIMM. If it isn't fully buffered (FB) it won't work, and you're probably going to want the 800 mhz stuff. Any Xeon, Mac or PC, requires the FB stuff.

    The Kingston RAM you linked to is not FB.
  4. Sesshi macrumors G3


    Jun 3, 2006
    One Nation Under Gordon
    It's best if it's Apple compatible, and equipped with a heavy-duty heat sink as on the standard Apple RAM. Most major vendors sell compatible RAM which is equipped in that way.

    Most of the actually 'Pro' Xeon workstations use forced air cooling which is directed straight at the RAM, using air which is usually separately taken in from the air used to cool the CPU assembly - which is why they use regular-looking DIMMs with simple flat aluminium heat spreaders. The Pro is different - and the cooling has been engineered (not very well) for low noise for consumers who're barely stressing the machine most of the time, and not for intensive running or high reliability. Memory which isn't capable of dissipating heat efficiently will result in problems sooner.
  5. marekkurlmann thread starter macrumors regular

    Mar 6, 2007
    So can anyone recommend some good, relatively cheap RAM that's worked well in your experiences? I'm curious what the price range is for RAM that's proven to work well with Mac Pros.
  6. Supaklaw macrumors regular

    Feb 8, 2008
    #1 Wait to buy the Mac Pro... they're probably releasing a new model in a few weeks and you could pick up a 2008 model for cheap, and the money you save can go to RAM. Or get the latest model, and have a faster Mac than you planned.

    #2 OWC, no question. They have 16 GB for $350.

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