Data written/red in activity monitor

Discussion in 'MacBook Pro' started by andymac2210, Oct 5, 2012.

  1. macrumors regular

    Joined:
    Jul 18, 2011
    #1
    I'm getting a bit concerned that my MBP is writing a lot of data to the HDD when I'm doing relatively little.

    I have mail, reeder, safari (granted with like 20 tabs), mamp, coda and photoshop open and although my computer has only been on for 12 hours I've 'written' 10gb of data to the SSD.
    It's not like I'm doing video editing or anything.

    What sort of read/write numbers are other people getting after similar up-times?

    [​IMG]
     
  2. simsaladimbamba

    Joined:
    Nov 28, 2010
    Location:
    located
    #2
    That is normal behaviour, temporary files (caches) have to be written sometime.

    Normally modern SSDs have a theoretical write/read limit of 10,000 to 100,000 cycles (P/E cycles), meaning if you had a 64 GB SSD and its cycle limit would be 10,000, you would have to write 625 TB to it, which would be 351 GB per day everyday for the next five years. Assuming those numbers vary and it would only be a tenth of that, it would still mean 35 GB per day, which under normal usage no average computer consumer does, not even with temporary files.

    I cannot offer any of my statistics, as I already copied dozens of GBs today.
     
  3. thread starter macrumors regular

    Joined:
    Jul 18, 2011
    #3

    That's interesting.
    I thought because I've had no page outs stuff would just be written to the ram first?
    Heck I've only had 1gb of page ins so far, I've hardly used the computer today.
     
  4. simsaladimbamba

    Joined:
    Nov 28, 2010
    Location:
    located
    #4
    Not everything gets stored in the RAM, temporary files, especially cache, get written to the mass storage device your OS resides on, in case the application needs access to it later. And Page-Ins can be ignored.

     

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