P4P800-VM & Kingston HyperX DDR400

Discussion in 'Asus' started by DRS, Jun 24, 2006.

  1. DRS

    DRS Guest

    (I'm relaying this for a third party; any and all errors are mine).


    ASUS P4P800-VM Rev 1.xx
    BIOS: AMI Version 1008.008
    Chipset: Intel i865P/PE/G/i848P Rev A2
    Southbridge: Intel 82801EB(ICH5)


    1. Kingston HyperX DDR-400 Model KHX3200UL/512 2-2-2-5
    Note: CPU-Z says this stick only has SPD timings for 200Mhz. Is this an SPD
    programming error?

    2. Kingston HyperX DDR-400 Model KHX3200UL/512 3-3-3-8
    Note: This stick has SPD timings for 200, 166 and 133Mhz.


    Intel Pentium 4 Northwood 2.80 GHz
    (Family) F (Model) 2 (Stepping) 9
    (Ext. Family) 0 (Ext. Model) 0 (Revision) D1

    Clocks according to CPU-Z 1.34.1:

    Core Speed: 2792.9 MHz
    Multiplier: x 14.0
    FSB: 199.5 MHz
    Bus Speed: 798.0 MHz

    The problem:

    Two sticks of Kingston DDR400 KHX3200UL/512 were purchased some months
    apart. If either stick is installed independently the FSB runs at 200Mhz
    (DDR400). When both sticks are installed (either in slots 1&3 or 2&4) the
    FSB runs at 133Mhz (DDR266). Obviously the goal is to have them both
    running at DDR400, even at the slower timings of the older stick. The
    system configuration seems to meet the requirements in the manual for
    running DDR400. No amount of tweaking the (limited) BIOS options can force
    anything other than DDR266 with both sticks installed.

    Apart from updating the BIOS to 1018 I've run out of ideas or explanations.
    DRS, Jun 24, 2006
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  2. DRS

    Paul Guest

    You can decode the SPD with this document:


    If you have a CAS3 module, the SPD will contain the minimum clock cycle
    time at CAS2.5 and CAS2.0. In the JEDEC doc, these are "CLX-0.5" and
    "CLX-1". For the CAS2 stick, they would have to be CAS1.5 and CAS1.0,
    and as far as I know, those don't exist. As a result, a CAS2 stick
    would probably only have one set of timings, and the two CLX entries
    would be zeroed. The BIOS would know, that for any clock speed below
    200MHz, the CAS would remain CAS2 as a minimum. On the other module,
    the BIOS knows that at 133Mhz, the slow module can do CAS2.

    It almost sounds like it is trying to run both sticks at the fastest
    common CAS, rather than the fastest common clock speed. If it did
    the latter, you'd be at 200MHz and CAS3, and a lot better off.

    Updating the BIOS sounds like an option. If you look at the BIOS
    listing, it warns if your current BIOS is before 1008, you should
    flash to 1008 as an intermediate point, using PPVM1008.exe inside
    the download file for 1008. Presumably that is updating the boot
    block. Then follow that with flashing to whatever later version
    you want to use.

    Paul, Jun 25, 2006
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  3. DRS

    DRS Guest

    Follow-up: updating the BIOS didn't help. Kingston were contacted via the
    supplier and recommended running at DDR266 2-2-2-5, which is what the BIOS
    is doing anyway. I presume they're working on the basis that since 266/2 =
    133 and 400/3 = 133 then DDR266 2-2-2-5 is effectively the same as DDR400
    3-3-3-8. Even if that's true I still reckon the BIOS is going about it
    DRS, Jul 12, 2006
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