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Thread: 128MB, What's the diff?

  1. #1
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    I'm trying to figure out what roughly $360 will get you (128MB vs. 128MB buffer). Also, what do you mean by "theoretical configurations utilizing 128MB DIMMs"? Are there any problems with 128MB DIMMs? Why not pay the extra $8 to get 64MB more? Is the best just to go with the 64MB DIMMs? --thanks

  2. #2
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    Hi

    You need to provide a bit more information with your question - what system are you trying to put this RAM in?. I suspect that the "theoretical configurations" refers to how much memory you could theoretically get (i.e. if I have 8 slots and I have 512 MB RAM chips, then does that mean I can have 4 GB of RAM in my machine (this is just a made-up case-in-point)) vs how much Apple says that that particular machine can handle ( or that the system can access)

    Chris

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    excuse me, it's a 9500/120 w/sonnet 400/G3. I'm quoting your memory info page for this model.

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  5. #5
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    um... yeah, that's the page that started my questions. I still don't get it though. What am I missing?

  6. #6
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    I think I understand what that page means...

    "The maximum amount of usable memory in the 9500-series is 768MB, in the form of twelve (12) 64MB DIMMs, although theoretical configurations utilizing 128MB DIMMs up to 1,536MB are conceivable."

    When the 9500 came out, 64 MB DIMMS may have been the biggest available (at that time) - therefore, with all 12 slots filled, you could only get 768 MB of RAM. Since then, 128 MB DIMMS have appeared on the scene, so in principle, you could populate the machine with 12 x 128 MB DIMMS and end up with 1.5 GB of RAM. Now the question is - Does the memory controller on the 9500 recognize that you now have that much memory? Or, because it's an older machine, is it unable to see that much RAM. In older versions of the MacOS, I think there was a limit as to how much RAM the OS was capable of working with (i.e. was it 1 GB?) but that has since been surpassed and at one point - pre OS X - I think it's a question of how much memory a program can be allocated (1.5 Gb?)

    There is no real problem with 128 MB DIMMs provided the motherboard memory controller is capable of (1) recognizing that they are there ie oh - slot 1 has a 128 MB DIMM in it and (2) recognizing how many there are..."Oh, I have 12 slots full of 128 MB DIMMS.

    Now - I have a 7300 which is comparable vintage, I think, and I have 6 x 128 MB DIMMS and 2 x 32 MB DIMMS in it and it's pretty happy so I would expect that your 9500 would be able to handle the 128 chips...

    Chris

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    This topic might help _ look at the last posting by LV re: his PTP...
    http://www.macgurus.com/ubb/Forum5/HTML/000342.html

    BTW - my PTP (9500 clone) has 2 x 128 MB sticks sitting in it and they work great - got them from the "Gurus.

    Chris

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    Oh! That makes sense. Now, how about the difference between the $50something and the $400 something modules?

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    The more expensive ones are the ones that are meant for those using Newer Technology boards:

    "Please note that 162244-compliant memory (required for NewerTech upgrades) is now available as a separate part number. If you have a NewerTech upgrade, please ensure that you order 162244-compliant DRAM. We do not, at this time, carry a 64MB DIMM which is 162244-compliant. If your Macintosh cannot accept a 128MB DIMM, and you have a NewerTech upgrade, make certain that you talk to us before ordering. Fortunately, only NewerTech upgrades require this memory. Upgrades from Sonnet, PowerLogix and XLR8 were long ago re-engineered to correct this incompatibility, and can accept correctly engineered DRAM with buffers beside 162244."

    If you are using the Sonnet board, then you should be O.K. w/ the cheaper one.. I'm using the cheaper ones in my XLR8 G3/500 PTP

    Chris

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    Apples memory guide "November 2000" says the 9500 can handle 128MB DIMM's and says that 768MB RAM have been tested and that theoretical limit is 1536MB RAM.

    This Apple memory guide is in pdf format and I got it from cnet.com - Mac downloads.

    Randy

  11. #11
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    Alright! Now we're getting somewhere! So, I've got a Sonnet G3/400 card (about 2 yrs. old) and I think I'm ready for two 128Mb dimms. Do you agree on the $50 something ones? Thanks so much for your patience and answers, I can't tell you how valuable this site is.

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    I recommend that you use the 128MB EDO DIMMs (yes, the $50 something variety). When you install them;

    If you're interleaving, put the largest DIMMs into slots A6 and B6, working down with your smaller DIMMs. I.E. A6=128, B6=128, A5=64, B5=64, A4=32, B4=32, etc.


    If you're trying not to interleave, place the DIMMs in dissimilar order so that each A bank position is different from the like B bank position. I.E.: A6=128, A5=128, A4=32, B6=32, B5=64, B4=64, etc.

  13. #13
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    green--matched pairs generally ensure the benefits of interleaving. My humble apologies if you already know this.

    lv--I've always bought DIMMs in pairs to gain said benefit (not that I would necessarily notice the dif). And I can certainly see a scenario where a lot of non-interleaved RAM is superior to a little interleaved, but why in dissimilar order as you've indicated?

    I ask because I'm anticipating a *really* interesting answer

  14. #14
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    Some machines, (Mostly those that can't have the L2 Cache removed) and some (mostly older) G3 upgrade cards have problems when memory is interleaved. This can also be a problem when dissimilar DIMMs are used in the machine. Deinterleaving the RAM frequently solves random crashes in this situation.

    At current prices, I would simply remove any older memory and replace them all with 128MB DIMMs. I haven't found a case where this didn't work, other than failling memory support components on the motherboard (OUCH!).

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