P4P800 Dlx DDR Dual Channel Mode Instability - Help?

Discussion in 'Asus' started by Roadhair, Jan 20, 2005.

  1. Roadhair

    Roadhair Guest

    Anyone know any reason why my memory would be less stable in dual channel
    mode when it's perfectly stable in single channel mode?

    System:
    P4P800 Deluxe MB
    P4 - 3.2 GHz processor
    Corsair XMS TwinX1024-3200LL memory
    WD Sata 120 GB boot drive
    WD Pata 80 & 200 GB data drives on VIA controller
    3 burners on primary controller
    Radeon 9800 Pro 128
    SB Live Value card
    450 watt PS
    Bios version is 1019. All settings are default except for disabled
    Hyperthreading and disabled onboard audio.
    Triple boot Win2K (x2) and XP from seperate primary partitions with
    Bootmagic. Use XP for gaming only. Xp was even more unstable than Win2K
    when running in dual channel mode.

    When I run it in dual channel mode I get mysterious blue screen reboots with
    messages like:
    IRQL_NOT_LESS_OR_EQUAL or
    PFN_LIST_CORRUPT or
    KMODE_EXCEPTION_NOT_HANDLED
    When it reboots from XP I will sometimes get some kind of hardware problem
    message stating that it's shutting down to protect the system.

    I've tried the ram in the blue and black slots. I've run single channel mode
    in all slot combinations and either 512 stick by itself in all slots with no
    issues. I wanted to buy another 1 gig set but am affraid it will begin
    crashing again as it will be in dual channel mode automatically.

    Thanks in advance,
    RH
     
    Roadhair, Jan 20, 2005
    #1
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  2. Roadhair

    Paul Guest

    The datasheet from Corsairmicro, says the product is 2-3-2-6.
    http://corsairmicro.com/corsair/products/specs/twinx1024-3200ll.pdf

    Slide 24 of this presentation says CAS-tRCD-tRP-tRAS is the order
    of the parameters listed above.
    http://corsairmicro.com/corsair/products/tech/memory_basics/

    You can check the basic settings of the hardware with:
    http://www.cpuid.com/cpuz.php

    And can get the free memory test tool memtest86 from:
    http://www.memtest.org

    Memtest86 is a tool that you load onto a blank floppy, and it
    boots the computer. It is also available in an ISO version for
    burning on a CD (if the computer doesn't have a floppy).

    I would start by entering the BIOS, and setting Vdimm voltage
    to a level useful for high performance memory. At least 2.6V
    is needed (as seen on the memory chip makers datasheets) and
    a value of 2.75V help a bit, without endangering the memory.
    Too low a voltage is a frequent reason for seeing errors.

    Also, while in the BIOS, make sure you aren't using any
    settings like "Turbo" or "StreetRacer" and the like, as
    some of these enforce a 2-2-2 memory setting without actually
    verifying that the memory can handle it.

    Boot into Windows and use CPUZ to verify your processor and
    memory frequencies. You can use CPUZ to tell whether the
    FSB is FSB800, CPU core 3.2GHz, memory timings 2-3-2-6 and
    so on. CPUZ will tell you whether you've set up things at
    normal levels, or are severely overclocking something by
    accident.

    Reboot the computer, and use the memtest86 boot floppy to test
    the memory. Memtest86 is a self contained boot program, and
    doesn't need DOS. The memtest86 program will format the blank
    floppy for you - the floppy won't have a normal file system
    on it, after memtest86 formats it for you, but the floppy
    will boot the computer just fine.

    A little more voltage could be enough to fix it. Changing the
    memory timings, to something a little more relaxed, like
    2.5-3-2-8 might help as well. Now, for many people, this
    would be a signal, that they need to RMA the memory. You
    may find that one stick is OK and the other one has errors,
    in which case it will be more obvious that one stick could
    use an RMA.

    If you cannot get enough help here, the Corsair support
    is over here:

    http://www.houseofhelp.com/forums/forumdisplay.php?forumid=128

    HTH,
    Paul
     
    Paul, Jan 20, 2005
    #2
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  3. Roadhair

    Roadhair Guest


    Ok,
    After much fiddling about I've adjusted the "AI Overclock Tuner" from
    standard to manual. This has allowed me to manually set the DDR voltage to
    2.75v. I set "Performance Mode" from Auto to Standard (It was never set to
    Turbo). Don't know if that really helps. Configuring the DRAM timings
    manually had little effect. DRAM timings were properly configured by SPD
    and CPUZ verified settings as 2-3-2-6. Memtest errors dropped at 2.65v and
    more so at 2.75v. I still recieve some errors now that I'm running it back
    in Dual-Channel mode (14 in test 5 and 5 in test 7 after four full passes)
    but no crashes or instability that I can tell. And relaxing the timing does
    not decrease the errors. Good call on the voltage. Should I be concerned
    that I'm not getting squeky clean test results from Memtest?

    Thanks,
    RH
     
    Roadhair, Jan 24, 2005
    #3
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