Confused with some responses about RAM upgrades

Discussion in 'iMac' started by iRobby, May 7, 2011.

  1. iRobby macrumors 6502a

    iRobby

    Joined:
    Mar 22, 2011
    Location:
    Fort Myers, FL USA
    #1
    I have been reading several threads regarding certain RAM configurations being slower than others based on slots. Below is what I thought were the best configurations:

    Ram options:
    buy Base: 4GB 2x2 (Apple)
    buy Base: 4GB 2x2 add 4BG Kit 2x2 = 8GB (OWC) $49.99
    buy Base: 4BG 2x2 add 8GB Kit 4x2 = 12GB (OWC) $104.00
    buy Base: 4GB base 2x2 remove it add 16GB Kit 4x4 = 16GB (OWC) $207.00

    HOWEVER:

    Some people (I've seen others in addition to the example below was well) are saying in the instance of an upgrade to 8GB:
    2GB x4 is faster than 4GBx2

     
  2. kevin2223 macrumors member

    Joined:
    Jul 31, 2010
    #2
    I don't think there is a huge difference between using 2GBx4 vs. 4GBx2, perhaps there is a few second difference in RAM-intensive tasks and benchmarks. The more meaningful upgrade would be adding 4GB/8GB/16GB, for 8GB/12GB/16GB totals, since you'd no longer be swapping to a slower HDD/SSD.

    If you are only adding larger RAM modules than the default ones, it wouldn't hurt to put them in the first two slots (moving the smaller ones to slots 3/4), but again, I don't know that there is any huge difference as long as they are in pairs.

    The 3rd link is slower because it is 1066MHz while Apple uses 1333MHz RAM, and usually it would default to the slower speed.
     
  3. Hellhammer Moderator

    Hellhammer

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    #3
    The IMC only supports dual-channeling so 4x2GB and 2x4GB both offer dual-channel bandwidth. There should be no difference in performance between them.

    If you want 8GB, go with the stock 2x2GB and buy 1x4GB from aftermarket. That leaves you an empty slot for future upgrades. I would also recommend NewEgg instead due to lower prices.
     
  4. qap macrumors 6502

    qap

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    Udine, Italy
    #4
    4x2gb could be faster 'cause the small RAM banks usually have a less latency timer but I don't know if change somethings with the iMac because the bios is different, anyway the speed difference is really small small, buy a good ram with the better price and don't worry about the size!

    ps: ram works with 2x2 dual channel and the others two slots the same
     
  5. iRobby thread starter macrumors 6502a

    iRobby

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    Mar 22, 2011
    Location:
    Fort Myers, FL USA
    #5
    Should I get all OWC sticks equaling 12GB 1 4GB kit 2x2 and 1 8GB Kit 4x2and forget the Apple since they got different MHZ? But all tnhe ones I see are 1333MHZ look below

    .

    judging by OWC more expensive vs NewEgg which is the better Ram

    8.0GB OWC Memory Upgrade
    2 x 4.0GB 1333MHz DDR3 SO-DIMM PC10600 204 Pin $104.00

    G.SKILL 8GB (2 x 4GB) 204-Pin DDR3 SO-DIMM DDR3 1066 (PC3 8500) Laptop Memory Model F3-8500CL7D-8GBSQ $69.99

    CORSAIR 8GB (2 x 4GB) 204-Pin DDR3 SO-DIMM DDR3 1066 (PC3 8500) Laptop Memory Model CM3X8GSDKIT1066 G $79.99

    Kingston 8GB (2 x 4GB) 204-Pin DDR3 SO-DIMM DDR3 1066 Laptop Memory Model KVR1066D3SOK2/8GR $79.99
     
  6. SiskoKid macrumors 6502

    Joined:
    Jul 12, 2008
    #6
    So since I got 16GB of RAM from OWC, does that mean my machine will run slower?
     
  7. theking79 macrumors 6502

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    Apr 28, 2009
    #7
    i am also confused about what slots the RAM go into, im buying an extra 2 x 4GB to boost my mac upto 12GB


    i need some confimation that this is the right configuration regarding which sticks go in each slot:

    2GB 2GB
    4GB 4GB

    (so top right and top left are both 2GB the way they are already in the mac)
    (bottom left and bottom right slots are both 4GB)

    i realy need some confirmation on this because i heard you need to place the ram in certain slots to enable dual channelling.
     
  8. Hellhammer Moderator

    Hellhammer

    Staff Member

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    #8
    Just put the modules into the empty slots. The existing pair should already be in dual-channel.
     
  9. George-gr macrumors newbie

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    May 4, 2011
    Location:
    Greeece
    #9
    question

    Hello guys,
    Does the base 21.5" 2011 imac has ram upgrade limit to 8GB?
    Is it possible to update to 16gb?
     
  10. Hellhammer Moderator

    Hellhammer

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    #10
    It supports 16GB but Apple only offers up to 8GB.
     
  11. paulrbeers macrumors 68040

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    Dec 17, 2009
    #11
    Just to fix this, this would be the worst way to upgrade. Yes it would leave you a slot for future upgrades, but you would lose the dual channel memory so instead of 128bit memory bandwidth, you would be limited it to only 64bit which would cause a reduction in overall system speed of anywhere from 10-15% in CPU intensive tasks.
     
  12. TMRaven macrumors 68020

    TMRaven

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    Nov 5, 2009
    #12
    Chances are the topic creator would sooner notice the performance increase in going from 4 to 8 gigs sooner than noticing the performance decrease by not having equal amounts of memory in either channel to keep it at dual channel bandwidth. That's also not to take away the fact that the memory controller could operate the ram in flex mode so only part of the ram gets dual channel while remaining is single channel.
     
  13. Hellhammer Moderator

    Hellhammer

    Staff Member

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    #13
    Source? All tests I've seen show that triple-channel provides only 1-2% better performance than single-channel.

    http://www.tomshardware.com/reviews/Intel-Core-i7-Nehalem,2057-13.html

    Besides, the 2x2GB would still run in dual-channel.
     
  14. George-gr macrumors newbie

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    May 4, 2011
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    Greeece
    #14
    Thanks a lot or your help!
     
  15. scramble103 macrumors newbie

    Joined:
    May 3, 2011
    #15
    so would it be a good idea to get the 4 to 8gb ram update for $200, or could I go to a computer store and have them install more ram for cheaper?
     
  16. Coolestdude macrumors member

    Joined:
    Mar 22, 2011
    #16
    A computer store shouldn't charge more then $50-60 to install RAM for you. But seriously, unless you are the type to pull your car up to the Full-Service island at the gas station, put it in yourself.
     
  17. Badger^2 macrumors 68000

    Badger^2

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    Oct 29, 2009
    Location:
    Sacramento
    #17
    NO! to both.

    You want the stock ram and add your own additional 8 gigs (2 x 4) to make 12.

    The ram is so easy to install my 7 year old daughter could do it. Paying anyone $50 to do it is just throwing money away.
     
  18. Dresevski macrumors 6502

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    May 6, 2011
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    Minnesnowda
    #18
    EZ Mode

    "NO!" is right. This is actually such an easy install that if you don't do it yourself you should probably not be upgrading it at all...? It's really simple (2 screws)
     
  19. iRobby thread starter macrumors 6502a

    iRobby

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    Mar 22, 2011
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    Fort Myers, FL USA
    #19
    i've decided on getting the OWC 16GB kit ad I believe it is 3 screws not 2
     
  20. Badger^2 macrumors 68000

    Badger^2

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    Oct 29, 2009
    Location:
    Sacramento
    #20
    skip the 16 gig upgrade, go with 12.

    8 gigs costs 100 bucks. That gives you 12 gigs when added to the original 4 gigs.

    but to go to 16 gigs you will need to spend 200 bucks (8 gigs x 2) -- meaning the difference in price from 12 to 16 is 100 bucks.

    So $100 for 4 gigs of ram. Ouch.

    Unless you are trying to push giant HD videos or mutli audio -- 16 gigs *might* be necessary.
     
  21. SiskoKid macrumors 6502

    Joined:
    Jul 12, 2008
    #21
    I hate to high jack the thread, but I asked this above as well and no one responded.

    I also got the 16GB from OWC, but I'm confused now if that makes things slower.

    Does it?
     
  22. scramble103 macrumors newbie

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    May 3, 2011
    #22
    excellent news! anyone have a link to what i should buy?
     
  23. Dresevski macrumors 6502

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    May 6, 2011
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    Minnesnowda
    #23
  24. iRobby thread starter macrumors 6502a

    iRobby

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    Mar 22, 2011
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    Fort Myers, FL USA
    #24
  25. alust2013 macrumors 601

    alust2013

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    On the fence
    #25
    To OP: my comment was referring to that specific link. It was 1067MHz vs. the 1333MHz already in the computer. 1067MHz has questionable compatibility with these new iMacs, and given that the two speeds are roughly the same in price, there's no point in buying slower memory.
     

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