Memory upgrade question (same old I know, but...different)

Discussion in 'Mac Pro' started by tribulation, Dec 28, 2006.

  1. tribulation macrumors regular

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    #1
    I've read the *many* posts about this already on here and elsewhere but still can't really find a definitive answer. I have a mac pro with 4x512MB RAM. I'd really like to upgrade to 4GB total, but want to do it the best way performance-wise. My question is the quad-channel over-talked-about question.....

    If I leave the 4x512 MB chips in there and buy 2 1GB chips, will this still be the best performance layout? Or will it slow down the other 512 chips by disabling the quad-channel mode thing? It's obviously a lot more money to toss the current chips and buy 4 1GB modules, but for arguments sake, would this theoretically be any faster than 4x512 + 2x1GB? Thanks.
     
  2. tribulation thread starter macrumors regular

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  3. StealthRider macrumors 65816

    StealthRider

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    #3
    From what I've heard, 4x1GB will be faster than 4GB of mixed modules.
     
  4. Father Jack macrumors 68020

    Father Jack

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    #4
    To be honest I'm not 100% sure, but in practice are you really going to see any difference ... I wouldn't think so.

    But then I may be wrong .... it has happened before (lol)

    FJ
     
  5. StealthRider macrumors 65816

    StealthRider

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    #5
    It'll be a few seconds' difference either way, most likely.
     
  6. tribulation thread starter macrumors regular

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    #6
    Hmmm...seconds is a lot of time....I was thinking more like milliseconds differences. If it's actually seconds, that's a big difference for me. Now the dilemma. Do I toss my current chips which is a lot of money down the tube; or just go with the bigger ones mixed anyways and hope that the extra memory justifies the (hopefully) slight delay.

    Or even what about getting 4 more 512MB chips? I know it limits my future upgrade options by filling up all slots but with this computer I would probably buy a new desktop before needing more than 4GB ram (or maybe not LOL). I have no clue :rolleyes:
     
  7. StealthRider macrumors 65816

    StealthRider

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    #7
    I'm talking about in long renders - in most day-to-day tasks you won't notice a difference.
     
  8. tribulation thread starter macrumors regular

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    #8
    Ok thanks :)
    I've been using Macs since the IIcx and never really was confused about this stuff. For some reason (maybe cause it's so expensive) I'm confused with all of these slots and "quad channel mode" etc etc. as it looks like so many others are on here. I wish Apple would publish something simple that explains in layman's terms what this all is and the best way to do it.

    So just to make sure of what you all said and sum it up, it would be worth sacrificing the small (probably very small) lag access time delay, in order to gain the added 2 GB of memory space, by keeping the 4x512MB chips I have and adding 2x1GB?

    I guess my main concern is, would it actually end up being *slower* than it is now? Thanks again everyone, much appreciated!
     
  9. THX1139 macrumors 68000

    THX1139

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    #9
    I love how people just guess at the answer to the OPs question. I suppose it's because they want to participate in the discussion even though they don't have anything worthy to add. I rank that the same as people who post "me too" kind of posts... like as if anyone really cares.

    To find the "correct" answer requires research. You aren't going to get an answer you can trust on this forum. What I think you should do is call Apple or check out the Apple forums. At least people over there seem to be a bit more informed than they do here. With that being said, I would highly doubt you will suffer too much slowness due to the difference in memory modules unless you are doing some major rendering (video and 3d) or pushing around a lot of pixels. That is when the milliseconds really start to add up. Either way, it's going to cost you a lot of money to know for sure.

    I'm in the same situation in that I have 2GB of ram in 4 modules. I want to upgrade to 4GB and will probably go with the 2 one gig chips to increase my ram to 4. If I'm not happy with the speed up, I'll sell the 512's on ebay and buy another 2 one gig chips. But first, I'll ask over at that Apple forums. ;)
     
  10. cynerjist macrumors regular

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    Nov 8, 2006
    #10
    i had the 4x512mb and added 2x1gb. i can tell you from my first hand experience it sure as hell is not slower than having just the 4x512mb. i don't know where this stuff comes from. the memory posts are really turning into a joke. i can work in multiple cs2 apps and flash along with safari and mail. it's great and i could not do that as easily with 2gb when i had alot of work open.

    as sure as i post this, some measurebator is going to show up with some benchmark or theory that says this or that. the bottom line is that 4gb has greatly improved my performance and productivity over the 2gb, despite the asymmetric (not 4x1gb) memory configuration.
     
  11. madyaks macrumors member

    madyaks

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    #11
    So let me ask this...
    If you have 2 gig, 4 sticks of 512.
    Would just adding 4 more sticks of 512 be bad? or really slow or something?

    The reason I ask is it is cheaper to buy the ram that way from apple than to buy 2 1 gig sticks.
     
  12. THX1139 macrumors 68000

    THX1139

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    #12
    As for speed differences, you are splitting hairs. The issue on going with all 512's is whether you want to fill all of your ram slots with low capacity ram. If you decide you need more ram later, then you're stuck with having to replace ram and taking a loss. If you know for sure you'll never need more than 4 gigs total or don't mind having to resell the 512's, then go for it.

    In my situation, I'm eventually going with two 1 gig sticks to add to my 4, 512's... so that I can keep two slots open for the possiblity to increase ram later. After that, if I need more ram, I'll be forced into replacing some of the 512's. But for now, it looks like 4 gigs of ram is the sweet spot for my needs.
     
  13. TheFuzz macrumors regular

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    #13

    i've ordered 2x1gb to add to my 4x512mb as well. how did you arrange them? did you just add the 2x1gb to slots 3 & 4 on riser 1?
     
  14. tribulation thread starter macrumors regular

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    #14
    I think that's what I'm going to do too. Just get 2x1gb. But was wondering the same thing. Which slots would be the best, I would have gone slots 3 & 3, 1 on each riser. But maybe that's not the best since it might be expecting another chip in the 2nd slot since they should go in as "pairs" I assume.
     
  15. slughead macrumors 68030

    slughead

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    Apr 28, 2004
    #15
    YOU WILL NOT NOTICE ANY DIFFERENCE IN USING 6 CHIPS VS 4.

    That is, unless, you run benchmarks all day, in which case you MIGHT (note: it's not significant enough for most tests to show a difference).
     
  16. cynerjist macrumors regular

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    #16
    Here is my 4GB configuration:
    Riser A:
    Slot 1: 1 GB
    Slot 2: 1 GB
    Slot 3: 512MB
    Slot 4: 512MB

    Riser B:
    Slot 1: 512MB
    Slot 2: 512MB
    Slot 3: empty
    Slot 4: empty

    some people have posted what i believe to be absolute nonsense about needing to have all four 512MBs in slots 1&2 on both risers and the 2x1gb in the higher slots. i love symmetry as much as the next person, but accessing the memory in slots 3&4 on either riser adds slightly more latency. therefore, i want my largest memory modules in slots 1&2 on each riser, in hopes that slots 3&4 won't need to be accessed as much. this is splitting hairs, really

    you need to install them in pairs on each riser.
     
  17. TheFuzz macrumors regular

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  18. tribulation thread starter macrumors regular

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