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When a 64 bit system isn't really 64 bit

Discussion in 'Tech Talk - Gadgets, Gizmos and Technology' started by dpeters11, Dec 13, 2013.

  1. dpeters11

    dpeters11 Hall Of Fame

    May 30, 2007
    So my niece in laws laptop was having problems so I took it home with me at Thanksgiving. They wanted me to fix it there, but without an Internet connection or tools, my options were limited.

    I determined the drive was bad, so I ordered a replacement, as well as more memory as the system didn't have much. Because there wasn't that much of a price difference, I ordered 8gb.

    The bios sees 8gb and Windows sees 8gb but half of it is listed as available. Are there 64 bit systems that cannot use more than 4gb? It is a few years old. Yes, I did install 64 bit Windows 7. It's home Premium, but even Basic has an 8gb limit. Premium is 16.

    Sent from my iPad using Tapatalk
  2. klang

    klang Hall Of Fame

    Oct 14, 2003
    Hardware limitation? I have an older Dell XPS desktop that will only take 4 GB even running 64 bit Windows 7.
  3. dpeters11

    dpeters11 Hall Of Fame

    May 30, 2007
    Something like that, just wondering why...though I hadn't actually tried to install more memory on a 32 bit system to see how memory over 4gb showed up.

    I did update the BIOS, just to see if that made a difference, it didn't. I was still running Windows Updates last night (500 meg even with SP1 already included) but can't imagine there would be anything there. Also was working on various drivers.
  4. Stewart Vernon

    Stewart Vernon Roving Reporter Staff Member Super Moderator DBSTalk Club

    Jan 7, 2005
    Kittrell, NC
    I haven't used my PC in quite a while... in Mac world now... but I seem to remember something about PCs reserving RAM equivalent to your video card RAM unless you disable something... so, for example if you had a 2GB ram video card installed and 8GB system ram, it would actually only show 6GB of usable system ram because it would match-reserve the same amount as you had on your video card.

    I think if this is the case that there was a way to turn that off... don't remember if it was video "mirroring" or what, different BIOS showed different names for similar config settings... but you might want to poke around in the BIOS and see what it shows for video card RAM and if there is a setting that also might be reserving additional matching system ram.
  5. FHSPSU67

    FHSPSU67 CE'er & Retired Engineer DBSTalk Club

    Jan 12, 2007
    Windber, PA
    Google "pc not recognizing all memory", especially any "Tom's Hardware" links,
    Been there, done that, but I can't even remember what my problem was.
  6. CCarncross

    CCarncross Hall Of Fame

    Jul 19, 2005
    Its probably using the rest of the RAM for shared video memory.....reducing the amount used for actual RAM...instead using it for video RAM. Very common practice in laptops. If you install over 4 GB on a 32-bit OS and it is recognized by the BIOS, it will only have up to about 3 1/2 GB available to the OS no matter how much you put in. If the BIOS is recognizing all 8GB then the system isnt limited to less than that.
  7. dpeters11

    dpeters11 Hall Of Fame

    May 30, 2007
    Looking more into it online, it seems like the system isn't 100% 64 bit. I'm seeing references that the AMD V105 only has a 64 but FPU, suggesting other components like the ALU are 32 bit.

    To me, kind of sounds like a device that only supports video over HDMI and not audio, and I think we did have ones like that early on.

    Sent from my iPad using Tapatalk
  8. RasputinAXP

    RasputinAXP Kwisatz Haderach of Cordcuttery

    Jan 23, 2008
    Old thread, but: No, Windows is caching stuff for you to use. I have 16 GB of RAM. I'm currently at a total of 16314 MB, 9389 Cached, 9921 Available, 586 Free. Or thereabouts. in general you're never going to have all of your memory "free".
  9. dpeters11

    dpeters11 Hall Of Fame

    May 30, 2007
    Nope, it wasn't caching. It truly was that the system cannot address more than 3gb of RAM. In my research, I found that there were some Intel chipsets that were the same way.

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