P4R800-VM won't boot up after RAM upgrade

Discussion in 'Asus' started by Keys'n'Stix, Sep 15, 2005.

  1. Keys'n'Stix

    Keys'n'Stix Guest

    Hi all,

    I've just tried to install a second 512MB DDR400 stick and can't get the PC
    to boot up. I bought the memory from the same store that built my PC.
    They're adamant it's a match for what's already in! They replaced the new
    stick, and it still won't boot up!!

    I've tried each stick individually, and it boots up fine. I've tried every
    conceivable combination of stick / channel / slots with no look.

    Store want to take the base unit in for a week, and charge me for sorting it

    BIOS settings don't correspond to what is in the manual - some menu options
    don't exist in the BIOS. I'm no great expert, but am PC literate.

    Anybody have any ideas as to what I can try??

    Many thanks.

    Keys'n'Stix, Sep 15, 2005
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  2. Keys'n'Stix

    Paul Guest

    There is a clue to the problem here:


    The problem relates to the BIOS design. There are no user
    accessable memory settings, unlike the Gigabyte board compared
    to the Asus board. I do not recommend the purchase of motherboards
    that do not have extensive DRAM settings in the BIOS - steering
    the operation of the BIOS by buying PC2700 RAM, is a stupid way to
    do things.

    The manual hints at the problem.

    Dual-channel (1) Populated x Populated x
    (PC3200) (Single-sided) (Single-sided)

    * This motherboard supports one single-sided PC3200 (DDR400)
    DIMM per channel only.
    * This motherboard may only detect PC2700 (DDR333) system
    memory when you install two PC3200 (DDR400) DIMMs in one
    channel or when you install double-sided PC3200 (DDR400) DIMMs.

    The first thing I would do, is get a copy of CPUZ from cpuid.com.
    (I don't know if Everest Home Edition, from Lavalys.com would aid
    in this job or not. It is another utility you can get for free.)

    Install your working single stick. Boot to Windows, run CPUZ, and
    get all available info about the RAM. It might tell you PC3200
    2-3-3-6 or the like.

    Now, get a copy of memtest86+ from memtest.org . It will format a
    blank floppy for you, and makes a self booting test (no OS required).
    Boot the memtest86+ floppy and test the original memory stick.
    Do a couple of complete passes error free, before concluding
    that stick is good.

    Next step, is shut down and install the new stick of memory.
    Run memtest86+ on the new single stick of memory, and see if it is
    error free for a couple of passes. If you are getting errors,
    take the stick back to the store and get your money back.

    Assuming the stick tests good, it is safe to boot into Windows.
    Run CPUZ and collect the vital statistics on the RAM.

    If both of these DIMMs are double sided 512MB memory (a very common
    form of construction), it could be that the BIOS is having trouble
    downclocking the memory to DDR333. At least, based on the description
    in the manual, that is what it appears is supposed to happen. If
    the two DIMMs have different nominal timing, maybe the BIOS is getting
    confused and craps out before achieving that setting ? (A Gigabyte
    user manual I looked at, suggests the chipset is flexible on memory
    clock rates, and if the chipset wants to, it can support DDR200,
    DDR266, DDR333, DDR400 memory clocking. So, this doesn't appear to
    be a limitation of the hardware.)

    Now, the question is, what to do if both DIMMs test good individually,
    but not together. Does the computer pass POST (power on self test) ?
    In other words, dues it get to the point of accessing the disk ?
    Or is it just a dead black screen ? If the two sticks are not matched
    in terms of the timings in the SPD of the DIMM, maybe that is enough
    to confuse the BIOS - normally a BIOS selects the slower of the
    two timing specs, and uses that to set up the CAS, tRCD, tRP, and so

    You also have two placement options for your two DIMMs. You can try
    running them in A1&A2 (single channel) or A1&B1 (dual channel). I
    suppose, if this is a timing confusion bug in the BIOS, it will fail
    in both cases.

    Some options - (2) is the lowest risk, but it sucks as a choice.

    1) Match the sticks. Tough to do if the store doesn't have the
    exact same part number. Matching the sticks may please the BIOS or
    it may not.
    2) Buy 2x512MB PC2700 (DDR333) memories. The BIOS will not try to run
    them at DDR400, so there are fewer potential gotchas. By matching
    them when you buy them, again, less risk that the BIOS gets hung up.
    3) Try 2x512MB PC3200 matched double sided memories, on the premise
    that by matching the memories, perhaps the BIOS can get past whatever
    bug it has got. This is only better than your current situation, in
    that the timing in the SPD of each DIMM is exactly the same. This is,
    after all, supposed to work at DDR333.
    4) Find the more obscure 2x512MB PC3200 single sided memories. That
    meets the manual's requirement of using single sided memory for
    this. I had a quick look, and cannot find any. It may take
    quite a bit of searching to find some (I know they are out there).

    You can see here, that at least Crucial thinks both PC2700 and
    PC3200 are supposed to work.


    Have you tried upgrading the BIOS ? I only see one BIOS that mentions
    anything to do with memory. But perhaps that will be the key to getting
    better behavior. Click the "BIOS" button:


    I guess according to these two threads, you are not alone.

    "P4R800-VM + DUAL Channel"

    "Asus P4r800-vm"

    Paul, Sep 16, 2005
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  3. Keys'n'Stix

    Keys'n'Stix Guest

    Many thanks for all your advice Paul. I'll try and get through it all over
    the weekend!

    With regards to POST, with both sticks in, it gets as far as accessing the
    hard disk, but not as far as spinning it up to speed before it crashes out.

    You're right about the BIOS being very poor. I'm not 100% confident with
    BIOS upgrades etc., but I've checked what I can in the BIOS settings, and I
    can't even get to setting the CAS! The manual says I should have options to
    change to FAST or SLOW, but they're not there. Checking what I can shows
    that the one good stick on its own is running at 333MHz.

    Also, I've noted that the two sticks have different numbers in brackets
    after the DDR400 on the labels. One is (2.5) the other is (3). (3) is the
    original stick. I've mentioned this to the store, and they say it's "nothing
    to worry about, they're the same". They also assure me that "even though
    there are chips on both sides of the sticks, they ARE single sided sticks".
    Running CPUZ will tell if that's true.

    I'm not happy that the store that built the PC can't sort this out for free,
    and in a quick turn around. They've even suggested that the MOBO could be
    faulty, and I might have to buy a new one from them, and pay to have it

    Thanks again, I'll keep you posted.

    Keys'n'Stix, Sep 16, 2005
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