Memory: 1.35V vs. 1.5V

Discussion in 'MacBook Pro' started by CorporateFelon, Jan 26, 2012.

  1. CorporateFelon macrumors regular


    Oct 26, 2007
    Boston, MA
    I've noticed recently that the prices on 16GB ram bundles(8GBx2) have sunk like a rock, and I've contemplated upgrading. Currently between ~$160 and ~$260.

    NewEgg has a couple of different bundles in stock, most seem be 1.5V variety. It has been noted that while the current MBPs are rated for 1.35V they are accepting the 1.5V rated modules.

    Is there a difference in using ram rated to use a higher voltage than what the logic board is rated at?
  2. thundersteele macrumors 68030

    Oct 19, 2011
    I think you got this wrong. The current MBPs by default use 1.5V RAM. People have successfully put 1.35V RAM into their MBPs, so it seems to work, and it seems to safe a very small amount of power.
  3. Acejam2k macrumors regular

    Jul 16, 2008
    I believe the 13" MBP uses 1.35V, some of the 15" MBP's use 1.35V as well. The rest of the 15" and 17" MBP's use 1.5V RAM.

    RAM kits that are rated for 1.35V will also function perfectly fine at 1.5V. They feature both voltage modes, and will run at whatever voltage the computer needs.

    I personally run 16GB of 1.35V Crucial RAM in my late-2011 2.5GHz i7 15" MBP, no issues here.
  4. dusk007 macrumors 68040


    Dec 5, 2009
    All MacBook Pros use 1.5V RAM currently without exception but this LV memory does work on 2011 notebooks on any older model it will probably just run in 1.5V anyway.
    It saves about as much as a HDD consumes. Bit less on ilde, about as much less under load as a HDD consumes when it is working.
    Idle difference is really small. Laod it saves like 2W. Yet the 16GB vs half that amount or 4GB of ram consumes more than you save so technically with LV RAM you don't actually save anything you just don't loose as much battery life.

    Personally I would think about upgrading. In a year you can probably buy 16GB for 50 bucks. So many people now seem to think upgrading to 16GB is a good idea but there are very few who can even make use of 8GB. Without VMs or some serious video editing, photo shopping nobody needs more than 4GB.
    Some people think more is better always. It used to be that way with ram but today RAM is abundant and RAM that isn't needed just costs and consume power (however little) but doesn't get the least bit of additional performance.
  5. CorporateFelon thread starter macrumors regular


    Oct 26, 2007
    Boston, MA

    I'm mainly going off all the reviews on Newegg. Most seem to say that the 13" and 15" are rated at 1.35V and there is a split between people saying the 17" is 1.5V. While every one says that they haven't run into any issues, I was mainly curious if there was an actual issue to worry about with the Voltage differences.

    I currently have an Early 2011 15". I have an 8GB set up and I bump up against the memory limit in my currently configuration and work load. Ideally I only need 10-12GB not the total 16GB, but they dont make 5gb or 6gb sticks.
  6. pizzaiolo macrumors newbie

    Nov 28, 2008
    Raleigh, NC
    I'm glad you started this thread CorporateFelon. Just today I opened a query with Corsair Memory tech support since the available information seems to be conflicting and a bit confusing. If I get a response I'll post it here.

    Now that I saw the point made in this thread about 16 GB consuming so much more power than the 8 GB, I want to do some more research on that as well, before I buy my upgrade.

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