Mac Pro memory risers interchangable?

Discussion in 'Mac Pro' started by netnothing, Aug 22, 2007.

  1. netnothing macrumors 68040

    netnothing

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    #1
    Was wondering, can the risers in the mac pro be switched from top to bottom or are the risers themselves tied to the slots they are in?

    -Kevin
     
  2. Fearless Leader macrumors 68020

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    Hoosiertown
  3. SDAVE macrumors 68040

    SDAVE

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    #3
    I agree, Just do work on one riser at a time so you won't get them mixed up. I think they are the same, but I have doubts.
     
  4. netnothing thread starter macrumors 68040

    netnothing

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    #4
    Only reason I ask is because I was reading the How much memory thread here: http://forums.macrumors.com/showthread.php?t=344244

    And per Multimedias post, I currently have my setup with 2x512 on Riser A and 2x1GB on Riser B. I'm going to switch them but was just curious whether I could just switch the risers themselves.

    Guess I'll play it safe and switch the RAM.

    Thanks.

    -Kevin
     
  5. Sean Dempsey macrumors 68000

    Sean Dempsey

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    Aug 7, 2006
    #5
    I swapped my risers yesterday, works fine for me.

    I've heard of people doing this. I cannot possibly see why it would matter, they appear to be functionally identical.
     
  6. SDAVE macrumors 68040

    SDAVE

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    #6
    Maybe each riser is identified differently? Dunno, I wouldn't take a chance on a working computer.
     
  7. ZachPruckowski macrumors member

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    Aug 15, 2007
    #7
    It shouldn't matter if the 2x512 is in Riser A or B. Because it's quad-channel, they're accessed simultaneously. The graphics just show the most RAM on top because they need a convention for general sanity, as there are way too many combinations.
     
  8. thxdave macrumors member

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    Aug 10, 2007
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    Florida
    #8
    Couldn't you look at the boards and see if there's a part number on them? If the number is the same, I can't imagine there would be any reason you couldn't switch them. After all, if you were putting in memory and had both boards out of the chassis, what would you do if you didn't remember which board came out of which slot?
     
  9. netnothing thread starter macrumors 68040

    netnothing

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    #9
    Well, I'm going to go with what Multimedia said on the issue:
    http://forums.macrumors.com/showpost.php?p=4075120&postcount=47

    From what he's said and what I've read is that he's right.

    -Kevin
     
  10. Father Jack macrumors 68020

    Father Jack

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    #10
    Switch the ram, just in case, and remember the largest ram chips should be inserted into riser A in slots 1 and 2 (at the back) .. :)
     
  11. netnothing thread starter macrumors 68040

    netnothing

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    #11
    Switched the RAM...not the risers. I was just more curious than anything. Looking at the Risers, they looked identical....but I still played it safe and switched the RAM itself ;)

    -Kevin
     
  12. Father Jack macrumors 68020

    Father Jack

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    #12
    A wise move Kevin .. :)

    Always make sure your largest ram sticks are inserted in the back slots in the top riser as they are addressed first. (or so I'm reliably informed) .. :cool:
     
  13. flyinmac macrumors 68030

    flyinmac

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    Sep 2, 2006
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    #13

    I had the same question as you a couple of days ago.

    I decided to open it up, and have a look for myself. Every component between the two risers (capacitors, resistors, various surface mount items, etc.) all matched exactly location for location.

    So, then I compared the part numbers and all other numbers between the two risers. All the numbers matched.

    So, then I swapped my risers, and the system has been working perfectly for 3 days now with the risers swapped.

    I originally opted to leave the stock Apple memory inserted in it's original slots. Then added the new modules to the second riser card.

    Then, I discovered the thing that indicated that the larger modules should go up-top (first riser). Whether there's anything to that, I don't know. I'd be interested in reading some real information instead of one guy's posting.

    Anyway, rather than swap 4 modules (which means more risk for failing to seat a module properly), I opted to swap the risers.

    No issues, no complaints. All is fine here.
     
  14. anim8or macrumors 65816

    anim8or

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    Aug 16, 2006
    Location:
    Scotland, UK
    #14
    You are best to keep the larger RAM modules in the top riser (A), the risers are interchangeable so don't have any fear about switching them.

    here is a nice little chart on how to arrange you memory according to sizes etc

    http://homepage.mac.com/tribe3/.Pictures/MemConfig.jpg

    Have fun!
     

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