Question about SIMM and DIMM combination in an old computer.

Discussion in 'Computer Support' started by thanatoid, Jul 4, 2007.

  1. thanatoid

    thanatoid Guest

    Hello gang,

    As some of you may recall, I have a computer which will be 10
    years old in September. It works fine. Really.

    Please don't just tell me to throw it in the trash and get a new
    one. When it dies for good, I will. At the moment I need nothing

    {I have a 2GHz machine for things requiring more speed than
    166MHz offers (which incidentally - IMHO - does not include
    accessing the internet).}

    Anyway, the almost-10-yrs-old machine has a PC Chips M572 MB,
    with 6 RAM slots. 2 are DIMM, 4 are SIMM.

    It can take a total of 256MB of memory and the manual provides 4
    SIMM/DIMM configurations by which this can be achieved.

    The 4 SIMM slots have a 16MB stick in each of them giving me
    64MB of RAM. It has always been this way.

    I happen to own a 64MB DIMM (it says 64MB 100/320/640 or
    something, and has a nonsensical non-brand brand name which
    escapes me at the moment). Pathetic as you undoubtedly will find
    this (and hopefully pity will inspire someone to help me), I
    have owned this DIMM for about 5 years but BION, just could not
    get the damn thing into either of the DIMM slots. Really. I
    tried and tried and it just wouldn't go in. So I just wrapped it
    in some pink antistatic foam and put it in a box somewhere.

    Well, for reasons not worth going into, today I decided to try
    one more time.

    It went in - but not after a ***LONG*** struggle with both

    Now here's the question:

    It is in slot DIMM2. The MB manual says "SIMM1 and SIMM2 and
    DIMM2 slots can not be used at the same time".

    It does NOT say "SIMM 1,2,3,4 and DIMM 2 can not be used at the
    same time", nor does it say they can - of course.

    When I put the DIMM into slot 1, the machine won't boot up. It
    makes a few preliminary noises but then stops.

    So the 64MB DIMM is in DIMM slot 2. The machine boots, the only
    difference being that instead of making a steady beep when
    "testing memory", it makes a low/slightly higher/low again
    triple continuous beep.

    It also now tells me it has 80 MB of RAM. I have, with some
    effort, managed to work out that means I have gained 16 MB of
    RAM from the 64 MB DIMM.

    Actually HERE's the question, sorry. /I think of the 2 options
    of saying not enough vs. too much, the 2nd is preferable, boring
    as it may be. But isn't that why we're all here?/

    I can't remember whether the 64MB DIMM has 4 or 8 chips on it,
    but is 3/4 of it just dead? Is there something else going on?
    Can a memory module work AT ALL when 3/4 (or whatever) of it is

    When dealing with a 166MHz machine with 64MB of RAM, an extra
    12MB is not unwelcome, although I have never had serious memory
    problems. Still, if you HAVE an extra 64 (or 16) laying around,
    why not use it (after 5 years)?

    More importantly, can any damage be done to the machine if the
    DIMM is 3/4 dead? Everything runs fine and I now have about 45
    MB of RAM free once 95B boots up instead of about 30, so unless
    there is a reason I should NOT, I intent to leave the ¿16/64¿
    DIMM in DIMM slot 2.

    So I guess the final question is: leave it in, take it out and
    throw it in the trash, or something else yet?

    Thank you for your patience and thank you for any replies which
    may come forward.

    thanatoid, Jul 4, 2007
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  2. thanatoid

    Ben Myers Guest

    I suspect the SIMM and DIMM slots that are adjacent to each share some
    circuitry, which is why they shouldn't be used simultaneously. Also, the M572
    seems to have jumpers for 3.3 and 5 volt memory. If the voltage setting for
    the DIMM is wrong, it could explain the unusual results.

    Ben Myers, Jul 4, 2007
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  3. thanatoid

    thanatoid Guest

    I believe I may have heard that before, actually... Old age...
    Thank you for your reply.

    I am glad you pointed out that the 2 voltages for DIMMs since I
    was not aware of that fact.

    I will mess around with the voltage jumpers, and see if doing
    that will either allow me to use slot 1 or to get more usable
    RAM from the stick.

    Since you did not say anything about any dangers, I am assuming
    that as long as everything runs OK, I am in no position to do
    harm to my computer. That was really the main concern.

    I looked at your link and did some more Googling but there is
    little out there besides what's in my original MB manual. One
    site DID provide a method for determining whether your DIMM is
    3.3V or 5V, but it also said no damage should occur if the
    voltage is set wrong. So I will experiment.

    Thank you again.

    thanatoid, Jul 5, 2007
  4. thanatoid

    CS Guest

    I doubt you'll get acceptable results by combining both RAM types. The
    whole idea of putting in both types of RAM slots (as well as two different
    CPU socket types) is to make upgrading a little less painful for folks
    hoping to use parts from their older computers in newer systems, or who want
    cheaper parts.

    Two different types or RAM is going to confuse your computer. Depending on
    the OS your using, you'll get freezing, blue screens, random restarts, and
    all manner of strange behavior. If your not fortunate, you'll get
    corruption in saved files.

    If scrounging Ebay for bigger SIMM's or DIMM's isn't to your liking, you
    might want to try looking for rare but, in theory cool, little gizmos that
    let you stick a bunch of SIMM's into them, shove them in the memory slots on
    the motherboard, rinse, repeat. Presto, a bunch more RAM.

    Personally, I doubt you'll see any real benefit, aside from the fun of
    playing with your computer or pretending your back in 1995 with $4500 to
    blow on RAM. As far as I know, most OS's that'll run on oldie-but-goodie
    computers can't use enormous amounts of RAM.

    If your after more performance, you can play with old and small but cheap
    SCSI drives that spin at insane speeds. You can also look for ways to
    better manage the RAM you have.

    As far as old computers go, you'd be surprised just how useful they can be.
    I've just recently dug out my ultra-rare but trusty Epson EHT-400, which is
    a very old pen tablet that just barely runs Windows 95 usefully. It wasn't
    nostalgia...I actually need a slower computer, and old version of Windows
    that can run DOS properly, and a serial port. The software I'm using won't
    work with anything newer, even Windows 2000.

    How old is this software? I purchased it from the manufacturer last month.
    Brand New!

    I'm using it to program Motorola two way radios. Some of these are 10 years
    old, and some are, like the software, brand friggin new.

    Motorola, it seems, sucks when it comes to software. And cell phones, but
    that's a different post.

    When you do get tired of your, um, collector's item, ask around your local
    radio shops if they want it. Most prefer laptops, but desktops can be handy
    in the shop. It'll at least save you the trouble of recycling the beastie.

    CS, Jul 6, 2007
  5. thanatoid

    thanatoid Guest

    I have solved (it would appear) the problem before I read your
    reply, but thank you anyway for taking the time. You make a lot
    of valid points. (For a complete update, see "Re: Question about
    SIMM and DIMM combination in an old computer - UPDATE" just
    posted to the microsoft.public.win98.gen_discussion.)

    I did get all that and more, and very bizarre amounts of RAM out
    of what SHOULD have been 128. But it ended up working OK. See
    the global update.
    I cleaned out the cobwebs etc. from my computer a few weeks ago
    and it has been slightly misbehaving since ("if it ain't
    broke..."). So I opened it up to see if I forgot to uncover the
    airhole on the HD or something, and while "in there", decided to
    give the 64MB DIMM I've had laying around for 5 years another
    try (see the global update).

    This is a 166MMX/64-now 96MB/95B machine and I have never really
    had any problems with it, and memory was usually sufficient
    unless I did something stupid like opening 8 browser windows at
    once. I just hate to have something sit around and do nothing
    (in this case the 64MB DIMM).
    I believed the same but was strongly reprimanded and corrected
    by an MVP who explained where the myth came from (I forget the
    explanation), and said that 95 can certainly use more than 64
    and that 98SE can certainly use more than 128. I in fact have a
    98SE machine with 256 MB RAM and it works very well. And this
    one - with 96 MB of RAM for the last 3.5 hours - is running just
    fine as well.

    But I think that 486's let alone 386's DID have very limited RAM
    Nah, I have never been about performance or speed. In fact I
    constantly have arguments with people who insult this machine
    which will be 10 yrs old in September but runs better and faster
    than most XP or Vista machines. And it does everything I need it
    to do (the other machine is a 2GHz for music conversions etc.)
    I'm a big fan of old stuff myself. I can't BELIEVE what people
    are throwing in the trash.
    Sounds very cool! I'll have to look it up on the web to see if
    there's a picture.


    Again, thanks for your reply.
    thanatoid, Jul 6, 2007
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