Memory questions

Posted:
in General Discussion edited January 2014
I am thinking of buying and Apple i7 iMac and if I do I will most likely upgrade the memory in it to 8gb by myself. First I have a few questions.



1. When I upgrade it can I just put 4gb in or is it better to add 8gb all of the same brand?



2. Does upgrading the memory myself void the apple care warranty?



3. What is the best memory out there to buy for the iMac?



4. I was looking at some memory and under the specs is says the following Specs: DDR3 PC3-8500, CL=7, Unbuffered, NON-ECC, DDR3-1066, 1.5V, 256Meg x 64.



What does the 256Meg x 64 mean cause I saw one that says 512Meg x 64?



Thank you for your answers.

Comments

  • Reply 1 of 5
    MarvinMarvin Posts: 14,180moderator
    Quote:
    Originally Posted by skives View Post


    1. When I upgrade it can I just put 4gb in or is it better to add 8gb all of the same brand?



    Matched memory can give you more memory bandwidth but your machine will ship with 4GB in 2 x 2GB so you will have to buy 8GB if you upgrade. If you buy 4GB, you will have to get a single 4GB chip and then you get 6GB total. An 8GB pack will have two matched 4GB chips. It usually doesn't matter if they aren't matched unless you have integrated graphics which the i7 doesn't.



    Quote:
    Originally Posted by skives View Post


    2. Does upgrading the memory myself void the apple care warranty?



    Only if you break it while installing it - generally no.



    Quote:
    Originally Posted by skives View Post


    3. What is the best memory out there to buy for the iMac?



    The 3 best brands are OWC, Hynix and Crucial. It shouldn't matter which you go for.



    Quote:
    Originally Posted by skives View Post


    4. I was looking at some memory and under the specs is says the following Specs: DDR3 PC3-8500, CL=7, Unbuffered, NON-ECC, DDR3-1066, 1.5V, 256Meg x 64.



    What does the 256Meg x 64 mean cause I saw one that says 512Meg x 64?



    The 256MB x 64 thing is the RAM density:



    http://www.kingston.com/tools/umg/umg04.asp



    Some computers aren't compatible with high density RAM. If you use Crucial's memory picker, you should be ok:



    http://www.crucial.com/store/listpar...%20Late%202009



    You can use the spec of that RAM to buy ones from other manufacturers if you find a better price.
  • Reply 2 of 5
    skivesskives Posts: 50member
    The new iMacs have 4 memory slots for a total of 16gb if you want. So can't I put 4gb more of memory (2x2gb) and it will show up as 8gb? Or is it better to have all the same brand of memory in the computer?
  • Reply 3 of 5
    MarvinMarvin Posts: 14,180moderator
    Quote:
    Originally Posted by skives View Post


    The new iMacs have 4 memory slots for a total of 16gb if you want. So can't I put 4gb more of memory (2x2gb) and it will show up as 8gb? Or is it better to have all the same brand of memory in the computer?



    I forgot they put 4 slots in. Yeah you can put in another 2 x 2GB - it doesn't really matter if the brands are mixed - just match the spec.



    The iMac actually supports faster RAM than they ship it with but you'd have to replace the whole lot for that to work. You could get as much as a 5% speed increase:



    http://timon-royer.com/en/52/is-it-p...5-and-core-i7/



    Not worth it IMO.
  • Reply 4 of 5
    dayrobotdayrobot Posts: 133member
    On most motherboards, every stick of memory will only be as fast as the slowest one!



    So keep that in mind when you will upgrade in the future...



    If compatible RAM you are buying is faster, it's best to remove the slower original RAM and compensate for that.



    I'll try to find a link that explains it better.



    There's a maximum speed that is tied to the main bus speed of the motherboard (the bus speed by the way also governs which processor is compatible), and there's a range of memory that is compatible with a machine, including that which can be slower than that maximum speed.







    Dan
  • Reply 5 of 5
    dayrobotdayrobot Posts: 133member
    Oh, and regarding brand-matching, don't worry about it. Just make sure that the specs match, and as i've said above, if you installed RAM is slower, it's best to just take it out and put in a whole set of that which is faster.



    You can always put old RAM on eBay rather than throwing it out. Someone will definitely want to double their OEM installed set







    Dan
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