14 Replies Latest reply: Dec 20, 2009 2:17 PM by nicholaspe
nicholaspe Level 1 (0 points)
My i5 should be here soon (whatever that means, and assuming the screen isn't cracked or flickering!). I know it has four slots, coming standard with a 2x2 set up. So I still have two slots to play with.

Does it make a difference how I distribute additional RAM in those slots? I would like to bump up to 8 gigs total at this point. However, I may decide to toss another 4 in down the road. I have heard that you should always put equal sticks in the slots (for some reason). Is this true or can I safely purchase a 4 gig stick to place in the third slot for now and leave the other slot available in case I decide to add in the future?

Any more savvy recommendations are welcome.



imac i5, Mac OS X (10.6.2)
  • jamesholden Level 3 (710 points)
    It's best for performance to keep them matched as the system can split the load equally between all sticks.
  • Kappy Level 10 (263,335 points)
    Four slots accommodating up to 16 GBs of RAM. Your user manual will provide information on installing RAM. RAM should be installed minimally in pairs. Please read the user manual thoroughly so you need not ask questions here that are explained in the manual.

    All the technical details will be provided in the tech specs for the computer which you can download at support.apple.com/specs/ or the same information should be provided with the specs found on the Online store.
  • nicholaspe Level 1 (0 points)
    Kappy, I am just trying to understand the reasoning behind it. Not trying to waist anyone's time with trivial questions. Sometimes you get a better explanation from a person than a manual. Plus the forums are full of tips and tricks not found in any handbook.

    Sounds like I will keep them in equal pairs, first for the sake of function, and second it appears that a single 4gig stick runs 3 times the price of a 2x2 set.
  • Kappy Level 10 (263,335 points)
    Reasoning behind what, exactly? There's nothing we can add than what's outlined in the user manual and is in the technical specs. There are no tips or tricks about the number of memory slots or the amount of memory the computer supports. So I'm afraid i don't understand what it is you need to know but cannot find. Maybe you could be more precise about it.
  • nicholaspe Level 1 (0 points)
    The question was asked in order to understand the advantages and disadvantages of using equal sticks. That's all. And, if "there's nothing we can add than what's outlined in the user manual and is in the technical specs" then these forums wouldn't exist. I regularly find excellent insight and tips from these forums that I would never find in a manual. I was curious to know if anyone had any additional guidance when adding RAM to my system. James above was able to give me a pretty straight forward answer without the "don't ask dumb questions" reprimand attached.

    While our conversation will be done after this post, I hope that future posters aren't simply directed to the manual. Many of us on here lack computer knowledge that you would likely consider to be most basic. That's why we post- for help. Keep that in mind in the future. I won't waste either of our time any longer with this.
  • Kappy Level 10 (263,335 points)
    Next time, then, ask the question you want answered. That wasn't the case here. What you asked is answered specifically in the manual and tech specs.

    I'm sorry that you didn't like my replies but it's not always going to be answers your prefer. Nor should you assume that "read the manual" isn't the best answer especially when you don't have the manual yet nor read it before posting your question.

    We have to direct users like you to read the manual because most of you don't. Instead they post questions here that are answered quite specifically in the documentation that came with the computer. I did not "reprimand" nor infer your question was "dumb." That was your inference simply because you did not like the reply. I've helped thousands of users and you are the first who considered "read it in your manual" an offensive reply. This says much more about you than it does about me. Keep that in mind in the future.
  • nicholaspe Level 1 (0 points)
    Oh, you mean I should have asked the questions I wanted answered like: "Does it make a difference how I distribute additional RAM in those slots?" Or "Is this true or can I safely purchase a 4 gig stick to place in the third slot for now and leave the other slot available in case I decide to add in the future? "

    You're right, I should have been specific... Also, I assure you I will read the manual once I receive it as do many "people like me". And of course I could go on line and search through the manual and get some form of my question answered. But since the Mac communities are usually so willing to lend a hand I thought I would throw out the questions to get some personalized answers. Ironically you did a pretty good job answering my question but obviously couldn't resist the jab. It is what it is, not an inference. If you're going to QA all the posts, then just don't answer the ones you are satisfied with. And yes, "Please read the user manual thoroughly so you need not ask questions here that are explained in the manual" would come across as a bit uninviting to most.

    I am glad you have helped thousands, and I hope you continue to do so. You and others like you are part of the reason owning a Mac is so great. It is a great community to belong to. I was obviously caught off guard by your response as it didn't seem to be in tune with the vibe in these forums. Hopefully your real intent was simply lost in the keyboard and I misunderstood the context of your response. If so we can just chalk it up as a misunderstanding. Let's burry this as it obviously is not what either of us intended. Sincere thanks for being willing to help. Happy Holidays. I hope to be celebrating mine with my new computer as it is yet to arrive...

  • canadaskyjumper Level 1 (0 points)
    That's how I would have taken the response too.

    I myself have not read the manual, and I ask questions on these forums as an alternative to reading the manual. If you do not want to waste your time answering questions that can be answered by reading the manual then don't. Pretty simple. I felt kind of an "elitist" vibe coming from that response.

    What's that thing mom used to say? "If you have nothing...."

    btw. Read the question. ie. He hasn't received the manual yet, and this is a good a spot as any to get info.
  • Randy Pozzi Level 2 (165 points)
    You do not need to install ram in matched pairs. Some previous MacBook pros could take 3GB or 6GB instead of 4GB and 8GB respectively. However, its BEST to install ram in matched pairs so they work together.My i7 iMac has maxed out matched pairs. Here is the reason:

    Most modern motherboards support dual-channel memory configurations. In brief, dual-channel technology lets the computer access each of two banks of memory on successive rises and falls of the system clock, rather than only once during the entire clock cycle. The performance gain, while not double, is significant. So, if you have only one stick of memory installed, buy a second one of the same size and type. If you have two sticks installed, buy an additional pair.

  • nicholaspe Level 1 (0 points)
    Thanks for the responses. Not looking for contention, just answers from people who know a lot more than me.

    Randy- That was the complete answer I was looking for. So in a nutshell, it can be done either way, but is best in pairs. In my case I would definitely like to take advantage of the dual-channel configuration. Thanks for the explanation. This question is now "double answered".

    I hope you are enjoying your i7. I am a little nervous about the flickering issues that are being reported. Still waiting for its arrival.

    Thanks to all for the help. Happy Holidays.
  • canadaskyjumper Level 1 (0 points)
    So... has anyone found a decent source for some cheaper DDR3 4G sticks?
  • Rick Lang Level 4 (1,230 points)
    The Core i5 and Core i7 processors have the memory controller on the die, i.e. not a part of the chip set. As has been indicated and as is explained in depth in Intel's datasheets on the Core i5/i7, best memory performance occurs if the memory sticks are installed in matched pairs. But if you want to add a single 4GB stick, you can do that. The existing two 2GB memory sticks that are already installed should be the first matched pair followed by the single 4GB stick. The memory performance of the matched pairs will continue to perform to spec with the i5/i7 (unlike some earlier memory controllers that degraded all memory performance to the lowest common denominator in terms of performance). The memory performance of the single 4GB stick will be degraded because it cannot take advantage of the dual channel access. But it will work and work reasonably well. Much of your work is going to be performed in the first 4 GB of installed memory so the slower memory often would not be noticed.
  • Big Rocco Level 1 (100 points)
    Nick, Great Questions, one's I surely have been thinking about also. I agree with you that manuals serve a great purpose and I always read mine, however, many times I read and think, 'what the heck does that mean though'. I come here for the answers. And yes, Kap's exchange with you was not the norm. All that being said, if the new iMac comes with 2G and 2G RAM, and I want to expand it and it will work reasonable well with a single 4G in the 3rd slot, I would probably buy the single 4G with the plan to add it's matching 4G as soon as possible. That would work right?

    Looking forward to upgrading soon to an i5 or i7.
    Maybe if I am really good, Santa will.......
  • nicholaspe Level 1 (0 points)
    You've got me thinking again... Your logic is good. If it is doing pretty good with the 2x2 set up that it comes with, adding a single 4G will most definitely not make it any slower, and will give the option of adding the second 4G when I want without having to replace and waste any of the sticks already there... Hmmm. But, a single 4G stick is significantly more expensive that 2 more 2G's. Atleast from what I have seen.

    I hope Santa hooks you up!