# Non-ECC vs ECC



## MacFreak (Nov 9, 2005)

Hi.. 

   I heard that ECC cause slow down but less error. If you use Non-ECC will run fast but lot of errors? Can anyone explain to me? 

ECC = Expensive
Non-ECC = Cheaper 


Since I am about to order new Quad G5 but not sure about which one better.


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## bobw (Nov 9, 2005)

The acronym "ECC" stands for Error-Correcting Code which means that ECC memory has built in mechanism to check the data stored in memory for errors that could cause instability and correct those errors on the fly. The "NECC" acronym stands for Non Error-Correcting Code which means that this type of memory does not posses the ability to check and correct data errors. Typically ECC memory is used in servers and high end workstations that perform many operations per second on a large amounts of data to ensure the integrity of the data when it's being moved within the system. NECC ram is typically used in home desktops and lower end workstations and costs slightly less then ECC RAM.

The choice between ECC and NECC RAM will not have much of a noticeable impact on the performance of the machine.


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## lurk (Nov 9, 2005)

Just for reference I had an old Pentium Pro with ECC memory in it that ran as a file server for like 5 years 24/7.  In all that time there was only one one-bit error detected and I think that was related to a power failure.  It is so not going to help you in your everyday life.

Where this is important is when you are building large clusters of machines.  If you have 150 boxes running 24/7 then the error rate I saw would mean that you would see an error once every 2 weeks.  Then it might matter if your distributed simulation takes 3 weeks to run 

P.S. Before you start in on teaching Probability 101 note the smiley.


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