Sorting out 72 Pin Simms/Powermac 7100

Discussion in 'Apple Collectors' started by bunnspecial, Feb 10, 2015.

  1. bunnspecial macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #1
    I decided to go through my "miscellaneous memory" drawer last night and get it organized-a task I've been putting off for a long time.

    Much to my pleasant surprise I found a couple of 64mb 60ns FPM 168 DIMMs, but that's a story for another day.

    In any case, I had three matched pairs of 72 pin SIMMs, and I'd like to install at least some of them in my 7100.

    Everything I found was 60ns, so from that standpoint they should be fine as the 7100 calls for 80ns.

    As far as capacity, the sticks I have are 8mb(x2), 16mb(x2) and 64mb(x2).

    Most of the references I find for the 7100 say that it accepts a maximum of 4x 32mb SIMMS. I'm wondering what chance the 64mb have of a. working and b. being recognized at full capacity. Or, more specifically, was the 32mb module size limit put in place because of what was available at the time the computer was made(as I know Apple often did then and still does now) or is it a real limit of the logic board/memory controller?
     
  2. MacTech68 macrumors 68000

    MacTech68

    Joined:
    Mar 16, 2008
    Location:
    Australia, Perth
    #2
    Hmm,

    OWC sells a 64MB under a 7100 listing, but says in the fine print:

    "This product works perfectly with 6100 class Power Macintosh systems. Some memory controllers in 7100 and 8100 Power Macintosh systems do work with these chips but that is not guaranteed."

    http://eshop.macsales.com/item/Other World Computing/72PS64MB/

    Everything else I see says 32MB SIMMS.

    Hardly definitive, I know. :(
     
  3. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #3
    Thanks-since I have them on hand I'll take the "try it and see" approach...

    If this were my 8500(which I have more RAM for, but have put off upgrading) I wouldn't do that. Since the ram is at least relatively accessible in the 7100, I'll give it a shot(and report my results back here).
     
  4. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #4
    I broke the computer down and installed 2x32mb and 2x64mb.

    On booting, it's only reporting 104mb...if my math is right, that's 1x32mb, 1x64mb, and the 8mb onboard. Or, possibly it's reading the 64s as 32s and not reading one of the 32mbs(or one of the 64mbs)

    It's running OS 8.1, which doesn't have the nice system profiler of OS 9 that breaks things down by ram socket so I can see what's working and what's not.

    I guess I need to get back to the ram sockets and at least blow them out good...
     
  5. MacTech68 macrumors 68000

    MacTech68

    Joined:
    Mar 16, 2008
    Location:
    Australia, Perth
    #5
    Odd.

    I used to use an LC475 for testing 72pin SIMMs (can be used one at a time).

    TechTool Pro 3.0.x should be able to show you the RAM configuration.
     

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