SDRAM with ECC or not?

Discussion in 'Buying Tips and Advice' started by fearnot, Dec 19, 2005.

  1. fearnot macrumors newbie

    Dec 19, 2005
    Hi Folks,

    I am working at a university and we are about to apply for a project. As the research requieres a computer for scientific simulation i sugested a Powerpc with 8 GB of ram.

    Now i am not sure if we need ram with ECC, as the longest a simulation should run would be 48 hours. Is ECC really worth it?

  2. TheMonarch macrumors 65816


    May 6, 2005
    Bay Area
  3. fearnot thread starter macrumors newbie

    Dec 19, 2005
    every research is important :)

    As i understand it the memory in ram gets corrupted after a while through external influence. I believe that as the memory gets updatet frequently (maximum 48 hours) it should be very unlikley for the memory to get corrupted in that timespan. And as the price for ECC-ram is double that of ram without ECC the question is if thats worth the money.
  4. CanadaRAM macrumors G5


    Oct 11, 2004
    On the Left Coast - Victoria BC Canada
    Pretty tough to second guess. Depends on the software you are running, and the length of time it is running between reboots, quitting and restarting the application or closing and reopening the data set. (The nature of soft memory errors is that they are erased when the data is erased or written over. They are a problem only when the data bit is read again after the error occurs.)

    ECC RAM will recover from single-bit errors, but it will still crash on errors of 2 bits or more.

    RAM errors are rare: soft errors (that is, not cause by a physical fault in the RAM module) are primarily caused by cosmic radiation. One figure I have seen is one error bit per 750 hours of operation. You'll have to do the math and estimate if this poses an unacceptable risk to your environment.

    If you compare equivalent modules, ECC RAM is not double the price of non-ECC (where did you get that idea?), it is more like 20% higher.
  5. fearnot thread starter macrumors newbie

    Dec 19, 2005
    thanks for your answer. We are running our simulations on a self written FORTRAN program. On the most the simulation should not take longer than 48 hours.

    Still one error bit per 750 hours is higher than i thought it would be and it looks like the extra 1500€ are worth it.

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