Looking to add more RAM to my late 2014 8gb iMac...which configuration would be better?

Discussion in 'iMac' started by ToddJ, May 1, 2019.

  1. ToddJ macrumors 6502

    Joined:
    May 23, 2008
    #1
    This might be a really dumb question but will it make a big difference if I add 16gb (8gb x 2) to the empty two slots on my iMac or would it be just as fast adding 8gb (4gb x 2)? I hear different things about RAM and I have heard in some situations if you have different size RAM there is not a big speed increase. Also, how bad (or good) is PNY ram? Normally I would buy Crucial but I have some gift certificates and Crucial isn't an option at where I want to buy it.
     
  2. MacUser2525 macrumors 68000

    MacUser2525

    Joined:
    Mar 17, 2007
    Location:
    Canada
    #2
    PNY is good ram. They all get the chips that go on the modules from the same suppliers there is next to no difference in any of the manufacturers. If you are not doing anything causing a lot of memory swapping the 4x4 in the machine will perform the same as the higher amount. It is when you exceed the ram in the machine and it has to swap to disk it slows you down. Do you use any programs that need large amounts of memory, like editing videos or loading large sound samples.
     
  3. ToddJ thread starter macrumors 6502

    Joined:
    May 23, 2008
    #3
    What about having different size RAM modules?
     
  4. MacUser2525, May 2, 2019
    Last edited: May 2, 2019

    MacUser2525 macrumors 68000

    MacUser2525

    Joined:
    Mar 17, 2007
    Location:
    Canada
    #4
    I am not certain there, I know with different sized modules on the same channel you lose 3% I think it is I have read in the past, as the dual channel will not function like that. When you put matched modules larger size I have no idea if the dual channel will still function. If doing all four the size being equal, the dual channel, I know from experience doing it still functions. I would need to be able to see a pc boot with the memory configured that way, then it will tell you if it is configured for dual channel. You can see it in the messages as it initializes the ram when mis-matched modules are present you do not see it say the dual channel. If you need that much ram it does not matter if you do lose the 3% anyways. Go with what you can afford for it, if not a pressing need for more, then no sense in it.

    Edit: Just had to know. I have such a machine it occurred to me to reboot my Debian server but Google found me the command to use in the first hit so no reboot necessary.

    Code:
    root@haswell:/home/seeder1# dmidecode -t 17 |grep Channel
    
    Locator: ChannelA-DIMM0
    
    Locator: ChannelA-DIMM1
    
    Locator: ChannelB-DIMM0
    
    Locator: ChannelB-DIMM1
    
    root@haswell:/home/seeder1# dmidecode |grep Size
    
    Runtime Size: 64 kB
    
    ROM Size: 8192 kB
    
    Installed Size: 128 kB
    
    Maximum Size: 128 kB
    
    Installed Size: 512 kB
    
    Maximum Size: 512 kB
    
    Installed Size: 3072 kB
    
    Maximum Size: 3072 kB
    
    Size: 4096 MB
    
    Range Size: 4 GB
    
    Size: 2048 MB
    
    Range Size: 2 GB
    
    Size: 4096 MB
    
    Range Size: 4 GB
    
    Size: 2048 MB
    
    Range Size: 2 GB
    
    Range Size: 12 GB
    
    
    
    
    As you can see matched pairs of 2gb and 4gb for 12gb total running in dual channel the Channel A & B in the first output.
     
  5. nambuccaheadsau macrumors 68000

    nambuccaheadsau

    Joined:
    Oct 19, 2007
    Location:
    Nambucca Heads Australia
    #5
    In real terms different size modules will not make any difference so go for it.
     
  6. ToddJ thread starter macrumors 6502

    Joined:
    May 23, 2008
    #6
    Who makes the best RAM? I was going to buy OWC, but a LOT of people recommend Crucial....
     
  7. MacUser2525 macrumors 68000

    MacUser2525

    Joined:
    Mar 17, 2007
    Location:
    Canada
    #7
    Whoever has the cheapest price, for the most part RAM is a commodity part. The only difference really is the name on the label, the chips themselves are made by the low number of companies in the business of making them. Most brands are just a repacking of them chips onto standard board designs.
     
  8. gilby101 macrumors regular

    Joined:
    Mar 17, 2010
    Location:
    Tasmania
    #8
    Keep them in pairs. The pairs can be different.

    You have 2x4GB. You can add 2xanything in the empty slots. So you add 2x4 or 2x8. Assuming it is compatible RAM there is no difference in RAM speed. But the Mac will run better with more RAM - how much depends on your workload.
     
  9. NoBoMac macrumors 68020

    Joined:
    Jul 1, 2014
    #9
    Have not priced in a long time, but, always had good luck with Crucial. And was competitive price-wise to others.

    Oops! Just realized Crucial is not an option per OP.
     
  10. ToddJ thread starter macrumors 6502

    Joined:
    May 23, 2008
    #10
    'Crucial not an option per OP?" what do you mean?
     
  11. DeltaMac macrumors G3

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #11
    ToddJ - you said that in your first post, remember?
     

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10 May 1, 2019