Last 4GB of ram not enabled?

Discussion in 'Memory' started by dcl, Oct 31, 2009.

  1. dcl

    dcl Member

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    Hey guys

    I've slapped 4 sticks of ram in to my GB UD4P. And while in the BIOS it detects all 8gb, only 4gb is 'enabled'. Anyone got any ideas?

    I've tried all sticks individually and they all work. CPUZ can see that there is 8gb of ram in the system, but Windows only see's 4gb. Anyone got any ideas?

    Cheers
     
  2. Dexamenus

    Dexamenus Member

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    32bit or 64bit operating system?
     
  3. OP
    OP
    dcl

    dcl Member

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    Just installed 7 64 bit. The problem is not the OS, it doesn't even show up with 8gb when it posts, just the 4. However The motherboard and CPUZ know there is ram plugged in the slots.

    Updating the BIOS presently. :o
     
  4. woodys_world69

    woodys_world69 Member

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    u may want to google your modo

    with my gigabyte i had issues with using all memory slots, it didnt like it because of dual channels etc and slowed my clock speed of the ram down

    i dunno maybe something to do with urs
     
  5. Whatsthatbeepin

    Whatsthatbeepin New Member

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    Tried updating your drivers yet? I ran Driver Genius pro after I loaded win7 64 helped fix alot of hardware issues on mine, might help. Also Check your MB for suport for 8 gig. I ran SIW on my Lappie which said 8g suported but my MB manufacturer still specs it as 4g
     
    Last edited: Oct 31, 2009
  6. OP
    OP
    dcl

    dcl Member

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    It's meant to support a max of 16gb of ram.

    This won't help. When it posts it doesn't enable/detect all 8gb, yet in the BIOS, it knows there are 4x 2gb sticks in the slots. Yet only the first 2 are enabled.
     
  7. OP
    OP
    dcl

    dcl Member

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    Could it be due to ram being single/double sided?
     
  8. Reaper

    Reaper Member

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    What ud4p motherboard is it, and what is the brand/model of the memory?
     
  9. MaCcA MaCcA

    MaCcA MaCcA Member

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    The Gigabyte P55UD4P (rev1.0?) using Corsair 1600mhz low voltage RAM for P55 chipsets (CMX4GX3M2A1600C9 Ram).

    I'm really at a loss here. :(

    edit: Posting on behalf of dcl
     
    Last edited: Nov 1, 2009
  10. oupimiquo

    oupimiquo Member

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    Two things:
    1) Update to the latest BIOS if you haven't already done so, and try with memory remapping both enabled and disabled. Award BIOSes have a bit of a history of wierd broken memory layouts that somehow manage to work with Windows - maybe 7 is choking on something that Vista/XP previously accepted.
    2) Drop the memory speed. Apparently some boards don't like more than one stick per channel at 1600 MHz. Try manually forcing it to 1333 (or even 1066) to see if that helps.
     
  11. Radley

    Radley Member

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    Is it 4 sticks of the same RAM?
     
  12. OP
    OP
    dcl

    dcl Member

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    Just updated to the last bios. Came out 2 days ago. Didn't help.

    I installed Win7 fresh.

    I've tried turning the ram speed all the way down and still no go.
    :(
     
  13. OP
    OP
    dcl

    dcl Member

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    Sure is. :o
     
  14. Yak

    Yak Member

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    Don't if it is exactly relevant, but I had an ASUS P6T not showing the full amount of ram... 8Gb instead of 12. It turned out one of the CPU pins in the socket was slightly out of alignment.

    By "CAREFULLY straightening" the pins with a piece of plastic and reseating the cpu the cpu's memory controller could see all of the memory.

    http://forum.corsair.com/v3/showthread.php?t=79471

    Yak.
     
  15. OP
    OP
    dcl

    dcl Member

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    ahh wow thats crazy. Could it 'see' the other ram though?

    Also, I tested the ram in a friends PC with the same cpu/mobo combo and his couldn't see it either. :o
     
  16. mr_wrxman

    mr_wrxman Member

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    May or may not apply to your motherboard, but I know mine has an option to limit the amount of memory available to the OS and maximises it for a 32bit OS. not sure what it's called but have a look.
     
  17. matthew-r88

    matthew-r88 Member

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    have u done a ram test on each chip individually like memtest maybe ones just NQR, what about in diff configs 2 @ a time, 3 @ a time etc, maybe you can narrow it down. otherwise different mobo config to try.
     
  18. OP
    OP
    dcl

    dcl Member

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    I haven't thoroughly tested the ram, but each stick individually boots in to windows.

    Here's some pics that might help.

    [​IMG]
    [​IMG]
    [​IMG]

    Anyone know what Channel and Rank interleaving are? The users manual doesn't really say.
     
  19. Yak

    Yak Member

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    I was a few weeks ago.. Can't quite remember all of the details, but I think the POST/BIOS said 8, when I had 6X2GB modules installed. I thought 8GB was weird considering they were triples...
    But it came good after the reseating etc..
    If you goolge 8Gig & ASUS P6T there are a few posts about the cpu socket mounting causing this issue.. A more valid test of the memory would be a different mobo.. if you can get access to one..

    Yak.
     
    Last edited: Nov 1, 2009
  20. OP
    OP
    dcl

    dcl Member

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    Someone on another forum has suggested that the max speed for all for slots is 1333. However the mobo is reading the XMP profile and setting it to 1600mhz and thus only allowing me to use 2 slots. I've tried disabling XMP stuff, but it hasn't seemed to make a difference.

    I might have to try some slower ram.
     

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