• RAM Voltage Question


    I wanted to buy another 4 GB RAM stick to install in a laptop and I thought I had all the info I needed to get the right kind: DDR3 PC3-10700 (667 MHz).

    However, the salesperson at the computer place asked me what voltage I needed and it was then I came to learn that RAM even had different voltages to begin with.

    He offered me both a 4 GB DDR3L 1.35 v stick and a 4 GB DDR3 1.5 v and told me I could easily return the unneeded one later.

    After checking with both CPU-Z and Speccy, I learned the current RAM slot was occupied by a 4 GB stick that was 1.5v.

    I then installed the new stick (which clearly states on both its package and on the sticker on the stick itself is 1.5v) in the second empty slot and then rebooted the computer.

    Everything booted as normal and Windows Task Manager shows that the additional 4 RAM is present and recognized.

    However, when I run both CPU-Z and Speccy again, they both tell me the voltage of the new stick is only 1.35 v. Huh??? How is this even possible? (And no, I didn’t install the other clearly marked low voltage stick by mistake.)

    I’m also concerned that running two sticks with different voltages will fry something.

    Any advice and expertise on this matter would be greatly appreciated.

    Viewing 6 reply threads
    • #2242890

      Much depends on which chipset you have and the BIOS defaults. If you don’t have an overclockable chipset (usually -Z suffixed), then you most likely have zero control over BIOS detection/default settings (RAM/CPU speeds/voltages, etc.).

      DD3L is later than DDR3 PC3-10700, and has a much broader range of settings/tolerances (my own 2x4GB Samsung DDR3L work fine from less than 1.25v@1600 > 1.65v@2133+ without trying on a -Z ‘board, much more constricted on a -B ‘board!). Trust your BIOS if it sets you up for DDR3L – unless you hit instability/booting issues (maybe from older settings, so reset the BIOS to optimised defaults, if you do).

    • #2251900

      The fact that the RAM is recognised tells you most of what you need to know – it is OK.
      Run a memory test utility if you want to be extra sure.

      cheers, Paul

    • #2252008

      Thanks for the insight satrow and Paul.

      I’m still very confused about all this though. To use an analogy, on a basic level, to me this would be like going to a store and purchasing a 12 pack of your favorite beverage. It clearly states on the package there are 12 cans in the package and there’s a packing slip inside confirming this number; however, when you take the cans out to put them in the fridge, there are only 10 instead of 12, if that makes any sense.

      Beyond this, do you have any recommendations on a memory test utility to use?

      • #2252056

        That’s easy … MemTest86 at PassMark Software, both free & paid versions.

        For legacy BIOS systems, need to run version 4 as current version 8.3 requires UEFI boot.

        Feature comparisons are shown here.

        Free & paid download links for versions 4 and 8.3 are here.

        Runs as stand alone program at boot from either CD/DVD, USB Drive or Floppy Drive.

        Win7 - PRO & Ultimate, x64 & x86
        Win8.1 - PRO, x64 & x86
        Groups A, B & ABS

    • #2252093

      Voltage is not size, it is pressure. It’s like putting air in your tyres, a little bit more or less makes virtually no difference.

      cheers, Paul

      1 user thanked author for this post.
    • #2252301

      I wouldn’t worry too much about the voltage. Standard DDR3 modules are rated for 1.5V. DDR3L is intended for low power devices and is designed to run at 1.35V but also must accept 1.5V to meet the specifications.

      • #2252343

        I don’t mean to keep harping on this, but this is the exact thing I can’t seem to understand:

        The RAM stick I successfully installed is a standard DDR3 module that is rated for and states it is 1.5V, yet both CPU-Z and Speccy show it as being 1.35V.

        Also, thanks for the suggestion on MemTest86, RDRguy.




        • #2252398

          What’s the part number of the module? Maybe we can learn something from that… it should be possible to look up the spec.




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    • #2252410

      Here ya go:

      G.SKILL SO-DIMM DDR3-1333 4GBx1

      CL9-9-9-24 1.5v

      Part No. F3-10666CL9S-4GBSQ

    • #2265428

      Without getting too complicated, a *lot* of modules that are rated at or *up to* 1.5V will happily run lower (say at 1.35v), they just won’t be happy *over* 1.5v (for an extended time)

      The reporting utility is (I would expect) showing you what voltage the modules are currently running at on that motherboard.

      As the others have said, provided all is stable and you have no issues, I’d ignore it and be happy 🙂

    Viewing 6 reply threads
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