1066MHz RAM running with 1333MHz in 2011 iMac

Discussion in 'iMac' started by danetello, Jun 16, 2011.

  1. danetello, Jun 16, 2011
    Last edited: Jun 16, 2011

    danetello macrumors 6502

    Dec 23, 2010
    London, UK
    I have got some spare RAM that was left from my old MacBook. I was going to use it for my new 2011 iMac but I saw that the iMac uses 1333MHz and I have got 1066MHz.

    Would the original 4GB 1333MHz work together with my 8GB 1066MHz?
    And what would be better: 4GB at 1333MHz, or 12GB at 1066MHz?
  2. NutsNGum macrumors 68030


    Jul 30, 2010
    Glasgow, Scotland
    This gets asked quite alot. The RAM will all run at the clock speed of the slowest RAM stick installed, in this case, 1066 MHz.
  3. Icy1007 macrumors 65816


    Feb 26, 2011
    Cleveland, OH
    Not worth it. It will only slow your system down.
  4. Bear macrumors G3

    Jul 23, 2002
    Sol III - Terra
    Not all systems gracefully use slower ram. (Even when they are supposed to.)

    Which is better? It depends on what you're running. If it's memory intensive the 12GB. If you're barely using 4GB, the 4GB will be faster.

    Now I see you're in the UK and I don't know ram prices there, but in the US I can get a memory kit for the iMac for under $100 US these days. If you really need the memory it might be better to sell your old memory to someone and just buy new memory.
  5. Bear macrumors G3

    Jul 23, 2002
    Sol III - Terra
    To add to my earlier post...

    Some systems that expect a certain speed ram won't work with slower RAM.
  6. Gunner86 macrumors member

    Jun 5, 2011
    I have a brand new imac purchased 2 weeks ago, i bought 8gb of 1066 memory by mistakse but ended uup installing it with the original 4gb of 1333, all it did was downclock the factory ram to 1066 aand everything works like a charm and no crash, the real world difference between 1066 and 1333 ram is very minimal and won't be noticed by 99.9% of users.


Share This Page