RAM needed to get use out of 4 Cores

Discussion in 'iMac' started by AcesHigh87, May 27, 2012.

  1. AcesHigh87 macrumors 6502a

    AcesHigh87

    Joined:
    Jan 11, 2009
    Location:
    New Brunswick, Canada
    #1
    I currently have 8GB of RAM (2x2 from apple, 2x2 third party) installed in my 2011 iMac. At the moment I don't do anything too heavy with the system but I'm building toward it more and more. I have noticed that After Effects rendering is a bit slow but never thought anything of it. Until today that is.

    I read a post stating that to get use of all 4 of the i7 cores you need 16GB of RAM. I'm not really sure of the logic behind this but basic math tells me that if this is the case I'm only using half of my processing power when rendering which would account for the long render times.

    What I'm wondering is if anyone could confirm this information and, if so, could someone offer a reason why this is the case? I know a decent amount about computers but haven't looked too far into stuff like this so I don't know exactly how it all works. I just want to try and get the most out of my system.
     
  2. John T macrumors 68020

    John T

    Joined:
    Mar 18, 2006
    Location:
    UK.
    #2
    You can read all the facts and myths about adding extra RAM to your machine. However, the only really reliable way to see if you do in fact need extra RAM is to check page-ins and page-outs via the Activity Monitor.
     
  3. philipma1957, May 27, 2012
    Last edited: May 27, 2012

    philipma1957 macrumors 603

    philipma1957

    Joined:
    Apr 13, 2010
    Location:
    Howell, New Jersey
    #3
    ^this.^


    In my case page ins 346.9 mb page outs 0 .

    This means I have not used more then my 8gb ram. When you page out you have exceeded your ram
    (jet engine speed) and you do a page out.

    You go to your hdd (horse and buggy speed if it is an hdd if it is a ssd propeller plane speed).

    So if your iMac has very few page outs (1 to 5 %) don't worry.

    If you have a 10 percent or more page out total you should get more ram. Ram is cheap right now.


    You have a 2011 iMac

    the ram below should work it is 100 dollars discount code of EMCNEHH45 brings it to 85 bucks

    http://www.newegg.com/Product/Product.aspx?Item=N82E16820144556


    this would get you to 20gb of ram it is very hard to be using 20gb of ram.




    this ram is 42 dollars this would get you to 12gb ram

    http://www.newegg.com/Product/Product.aspx?Item=N82E16820231342

    this may be enough for your machine and how you use it.


    just see that you get page outs if you don't get them you have another problem
     

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  4. 12dylan34 macrumors 6502a

    Joined:
    Sep 3, 2009
    #4
    Thanks for that, that's a useful thing to know. I'm at like 20%, so I definitely need more memory...Well, I guess I sort of knew that, but It solidifies my decision to get a ton on RAM for my next machine.
     
  5. AcesHigh87 thread starter macrumors 6502a

    AcesHigh87

    Joined:
    Jan 11, 2009
    Location:
    New Brunswick, Canada
    #5
    Thanks for the clarification. I knew of the Page Outs and stuff that you guys mentioned (mine only hit high when, as previously mentioned doing AE Work) but it's good to know that what else I've read was simply a rumour and that my card is running strong regardless of my RAM amount.

    I may upgrade at some point but don't think I really need to at the moment. I think when I do though I might get to 20GB. 8GB modules these days go for around 50 bucks so I can pay about the same to get 2x8GB as it would be for 4x4GB. Plus with only 2 new sticks I can keep 4GB that's already in the iMac. I appreciate that suggestion, I was considering it but you posting it confirms that it would work fine as I'd hoped.
     
  6. arri macrumors newbie

    Joined:
    Aug 7, 2008
    #6
    Memory and Multiprocessing

    HI. you need enough Ram installed. then you need to set memory and multiprocessing preferences to render multiple frames simultaneously. go to After Effects: Preferences: Memory and Multiprocessing. check mark: render multiple frames simultaneously. set Ram to at least 2 gb per core in the selection box, and set CPUs reserved for other processes as you wish, which will determine actual CPUs used for rendering in After Effects. After Effects runs optimal on a minimum of 2 gb Ram per core, which means per thread on a hyperthreaded cpu. This is Adobe guidelines, not some myth or BS.
    see ya, s
     
  7. AcesHigh87 thread starter macrumors 6502a

    AcesHigh87

    Joined:
    Jan 11, 2009
    Location:
    New Brunswick, Canada
    #7
    So, if I understand correctly, AE will use my cores but needs to be setup properly to use them at an optimal level? Therefore, as it stands on my 8GB of RAM and 4 core CPU I can offer it 2GB of RAM per core. However, if I upgrade to 20GB of RAM (for example) I could set it to 5GB of RAM per core?

    That is also completely assuming I only have AE running a render at the time and am not doing anything else. Or will AE compensate if say I open a new application during the render process?

    It does seem like this question is turning more into "How does AE handle things" and less "how much RAM do I really need"

    Edit: Just considered something too. Can't the i7 hyperthread to, essentially, 8 cores? Would that mean that I'm only running AE on 1GB of RAM per core?
     
  8. arri macrumors newbie

    Joined:
    Aug 7, 2008
    #8
    More Ram is Good

    Hi. if you have other Adobe applications installed, After Effects will reserve some Ram for them that AE can not use. you set your CPUs reserved for other applications as you wish to determine what you want to give other non adobe applications running, which will determine CPUs reserved for After Effects. go look at the Preferences to see what i am telling you. My selection box only allows 3 gb per core (thread) for After Effects on an 8 core mac pro with 32 gb of RAM.

    see ya, s
     

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