P5B=VM Memory Use

Discussion in 'Asus' started by Dewayne Thomas, Jun 8, 2007.

  1. I just put a system together using an ASUS P5B-VM with an Intel Core 2
    Duo 6400 CPU. I wanted to use 2 GB memory (4 sticks of 512MB Kingston
    DS) as listed in the manual as qualified memory for this MB. The
    system runs normal and stable with 1 GB mem, but with 2 GB, all four
    mem slots filled, it's unstable as hell and fails memtest big time.
    Using the settings listed on page 2-19 of the manual in all various
    combinations makes no difference. I left the mem & CPU voltages in
    auto as I really don't have a good feel for the impact they would have
    on the system if I imput something wrong.

    I have Win XP installed and it runs fine with 1 GB memory. I installed
    a ATI X 1950 Pro express 16 card in it but it ran fine with the
    onboard video also.

    Any one running this same MB with all mem slots filled, or have any
    suggestion on why the board wont handle 2 GB mem>
    Dewayne Thomas, Jun 8, 2007
    #1
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  2. Dewayne Thomas

    Robv Guest

    Dewayne Thomas wrote:
    > I just put a system together using an ASUS P5B-VM with an Intel Core 2
    > Duo 6400 CPU. I wanted to use 2 GB memory (4 sticks of 512MB Kingston
    > DS) as listed in the manual as qualified memory for this MB. The
    > system runs normal and stable with 1 GB mem, but with 2 GB, all four
    > mem slots filled, it's unstable as hell and fails memtest big time.
    > Using the settings listed on page 2-19 of the manual in all various
    > combinations makes no difference. I left the mem & CPU voltages in
    > auto as I really don't have a good feel for the impact they would have
    > on the system if I imput something wrong.
    >
    > I have Win XP installed and it runs fine with 1 GB memory. I installed
    > a ATI X 1950 Pro express 16 card in it but it ran fine with the
    > onboard video also.
    >
    > Any one running this same MB with all mem slots filled, or have any
    > suggestion on why the board wont handle 2 GB mem>


    Anytime you add memory, that additional memory draws current, making the
    total load of the memory voltage higher. The fix is simple: go into the
    BIOS and increase the voltage for the memory. Increase by one step,
    test the system and if it is not stable, increase the voltage again.
    Repeat till you have stability, although you shouldn't have to go too
    far to fix the problem.
    Robv, Jun 8, 2007
    #2
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  3. On Fri, 8 Jun 2007 14:08:23 -0400, "Robv" <>
    wrote:

    >Dewayne Thomas wrote:
    >> I just put a system together using an ASUS P5B-VM with an Intel Core 2
    >> Duo 6400 CPU. I wanted to use 2 GB memory (4 sticks of 512MB Kingston
    >> DS) as listed in the manual as qualified memory for this MB. The
    >> system runs normal and stable with 1 GB mem, but with 2 GB, all four
    >> mem slots filled, it's unstable as hell and fails memtest big time.
    >> Using the settings listed on page 2-19 of the manual in all various
    >> combinations makes no difference. I left the mem & CPU voltages in
    >> auto as I really don't have a good feel for the impact they would have
    >> on the system if I imput something wrong.
    >>
    >> I have Win XP installed and it runs fine with 1 GB memory. I installed
    >> a ATI X 1950 Pro express 16 card in it but it ran fine with the
    >> onboard video also.
    >>
    >> Any one running this same MB with all mem slots filled, or have any
    >> suggestion on why the board wont handle 2 GB mem>

    >
    >Anytime you add memory, that additional memory draws current, making the
    >total load of the memory voltage higher. The fix is simple: go into the
    >BIOS and increase the voltage for the memory. Increase by one step,
    >test the system and if it is not stable, increase the voltage again.
    >Repeat till you have stability, although you shouldn't have to go too
    >far to fix the problem.
    >


    The selections for the mem voltage start at 1.8V up to 1.95V in
    increments of .05. I went up to 1.95 and memtest still failed. I was
    hestant to go beyond that with out some knowledgable suggestions.

    Thank, Robv, for the info though. I don't know if you can keypad in a
    setting, but if you can what would be the max voltage I could use
    without frying something?
    Dewayne Thomas, Jun 8, 2007
    #3
  4. Dewayne Thomas

    Robv Guest

    Dewayne Thomas wrote:

    [snip]

    >> Anytime you add memory, that additional memory draws current, making
    >> the total load of the memory voltage higher. The fix is simple: go
    >> into the BIOS and increase the voltage for the memory. Increase by
    >> one step, test the system and if it is not stable, increase the
    >> voltage again. Repeat till you have stability, although you
    >> shouldn't have to go too far to fix the problem.
    >>

    >
    > The selections for the mem voltage start at 1.8V up to 1.95V in
    > increments of .05. I went up to 1.95 and memtest still failed. I was
    > hestant to go beyond that with out some knowledgable suggestions.
    >
    > Thank, Robv, for the info though. I don't know if you can keypad in a
    > setting, but if you can what would be the max voltage I could use
    > without frying something?


    What is the minimum voltage required for that memory? If you're not
    sure, give me the exact model number, etc. of the memory you have. I
    know it's 512 MB sticks and it's Kingston, but the exact model/part
    number will help to find the voltage requirements.
    Robv, Jun 8, 2007
    #4
  5. Dewayne Thomas

    Paul Guest

    Dewayne Thomas wrote:
    > I just put a system together using an ASUS P5B-VM with an Intel Core 2
    > Duo 6400 CPU. I wanted to use 2 GB memory (4 sticks of 512MB Kingston
    > DS) as listed in the manual as qualified memory for this MB. The
    > system runs normal and stable with 1 GB mem, but with 2 GB, all four
    > mem slots filled, it's unstable as hell and fails memtest big time.
    > Using the settings listed on page 2-19 of the manual in all various
    > combinations makes no difference. I left the mem & CPU voltages in
    > auto as I really don't have a good feel for the impact they would have
    > on the system if I imput something wrong.
    >
    > I have Win XP installed and it runs fine with 1 GB memory. I installed
    > a ATI X 1950 Pro express 16 card in it but it ran fine with the
    > onboard video also.
    >
    > Any one running this same MB with all mem slots filled, or have any
    > suggestion on why the board wont handle 2 GB mem>
    >


    Perhaps you could use CPUZ, to verify that the settings in the BIOS
    are being used.

    http://www.cpuid.com/cpuz.php
    http://www.cpuid.com/download/cpu-z-140.zip

    Compare the numbers, to the ratings for your RAM.

    The "registers dump" function, will make a text file for you, if you
    ever need to copy and paste any of the info. The raw SPD EEPROM info
    appears just below "Dump Module #1" etc.

    Paul
    Paul, Jun 8, 2007
    #5
  6. Dewayne Thomas

    RobV Guest

    Paul wrote:

    [snip]

    > Perhaps you could use CPUZ, to verify that the settings in the BIOS
    > are being used.
    >
    > http://www.cpuid.com/cpuz.php
    > http://www.cpuid.com/download/cpu-z-140.zip
    >
    > Compare the numbers, to the ratings for your RAM.
    >
    > The "registers dump" function, will make a text file for you, if you
    > ever need to copy and paste any of the info. The raw SPD EEPROM info
    > appears just below "Dump Module #1" etc.
    >
    > Paul


    Excellent suggestion.
    RobV, Jun 8, 2007
    #6
  7. On Fri, 8 Jun 2007 16:41:41 -0400, "Robv" <>
    wrote:

    >Dewayne Thomas wrote:
    >
    >[snip]
    >
    >>> Anytime you add memory, that additional memory draws current, making
    >>> the total load of the memory voltage higher. The fix is simple: go
    >>> into the BIOS and increase the voltage for the memory. Increase by
    >>> one step, test the system and if it is not stable, increase the
    >>> voltage again. Repeat till you have stability, although you
    >>> shouldn't have to go too far to fix the problem.
    >>>

    >>
    >> The selections for the mem voltage start at 1.8V up to 1.95V in
    >> increments of .05. I went up to 1.95 and memtest still failed. I was
    >> hestant to go beyond that with out some knowledgable suggestions.
    >>
    >> Thank, Robv, for the info though. I don't know if you can keypad in a
    >> setting, but if you can what would be the max voltage I could use
    >> without frying something?

    >
    >What is the minimum voltage required for that memory? If you're not
    >sure, give me the exact model number, etc. of the memory you have. I
    >know it's 512 MB sticks and it's Kingston, but the exact model/part
    >number will help to find the voltage requirements.
    >

    The part # is KVR800D2N5K2/1G , Chip # is K4T510830C.The memory Module
    Spec list the mem voltage @ +1.8 (+/- .1V) . It also list the power
    as 1.872 W (operating per module), which I presume is the min PS
    output fed to the mem slot. I have a new Thermaltake TR-2-500W PS,
    which should supply the V needed. I'll be running Vista Premium on
    this system so would like to have the 2 GB mem if I can get it on
    this board.
    Dewayne Thomas, Jun 8, 2007
    #7
  8. Dewayne Thomas

    RobV Guest

    Dewayne Thomas wrote:
    > On Fri, 8 Jun 2007 16:41:41 -0400, "Robv" <>
    > wrote:
    >
    >> Dewayne Thomas wrote:
    >>
    >> [snip]
    >>
    >>>> Anytime you add memory, that additional memory draws current,
    >>>> making the total load of the memory voltage higher. The fix is
    >>>> simple: go into the BIOS and increase the voltage for the memory.
    >>>> Increase by one step, test the system and if it is not stable,
    >>>> increase the voltage again. Repeat till you have stability,
    >>>> although you shouldn't have to go too far to fix the problem.
    >>>>
    >>>
    >>> The selections for the mem voltage start at 1.8V up to 1.95V in
    >>> increments of .05. I went up to 1.95 and memtest still failed. I was
    >>> hestant to go beyond that with out some knowledgable suggestions.
    >>>
    >>> Thank, Robv, for the info though. I don't know if you can keypad in
    >>> a setting, but if you can what would be the max voltage I could use
    >>> without frying something?

    >>
    >> What is the minimum voltage required for that memory? If you're not
    >> sure, give me the exact model number, etc. of the memory you have. I
    >> know it's 512 MB sticks and it's Kingston, but the exact model/part
    >> number will help to find the voltage requirements.
    >>

    > The part # is KVR800D2N5K2/1G , Chip # is K4T510830C.The memory Module
    > Spec list the mem voltage @ +1.8 (+/- .1V) . It also list the power
    > as 1.872 W (operating per module), which I presume is the min PS
    > output fed to the mem slot. I have a new Thermaltake TR-2-500W PS,
    > which should supply the V needed. I'll be running Vista Premium on
    > this system so would like to have the 2 GB mem if I can get it on
    > this board.


    Yes, found it. It's been my experience that when you add modules, you
    have to raise the memory voltage. I never used Kingston, but the memory
    I have now is Corsair, spec voltage is 1.9v. Ran memtest86+ with no
    problems with one stick plugged in. When I installed the second stick,
    a few random memory errors showed up. I raised the memory voltage to
    1.95, then to 2.0, then to 2.05v before the system ran fine, with
    memtest86+ and Prime95 with the system running.

    I've used OCZ and Crucial memory in other systems and had the same
    experience. I was curious about this and called Corsair, whereupon the
    support person explained that sometimes the voltage shown in the BIOS is
    not the actual voltage due to loading (extra modules) and/or the
    hardware reporting the incorrect voltage. It was a canned answer, as I
    could hear him reading it. However, he said nothing about the max
    voltage to try, and was nonplussed about raising the voltage even more
    than 2.0V.

    If spec is 1.8V and 1.95 still isn't stable, I would go to 2.0V and no
    higher than 2.1V. If you are uncomfortable doing that, you could return
    the modules you have for another pair and you may get modules that work
    with less voltage.

    Paul may have different advice for you. My advice is above, gained
    through my experiences, but getting more diverse advice always helps.
    :)
    RobV, Jun 8, 2007
    #8
  9. On Fri, 8 Jun 2007 17:16:43 -0400, "RobV" <>
    wrote:

    >Paul wrote:
    >
    >[snip]
    >
    >> Perhaps you could use CPUZ, to verify that the settings in the BIOS
    >> are being used.
    >>
    >> http://www.cpuid.com/cpuz.php
    >> http://www.cpuid.com/download/cpu-z-140.zip
    >>
    >> Compare the numbers, to the ratings for your RAM.
    >>
    >> The "registers dump" function, will make a text file for you, if you
    >> ever need to copy and paste any of the info. The raw SPD EEPROM info
    >> appears just below "Dump Module #1" etc.
    >>
    >> Paul

    >
    >Excellent suggestion.
    >

    Thanks, guys, I'll let the info I've gathered today cook awhile and do
    some more investigating with a register dump. Last resort I can jack
    the mem voltage up to where something smokes, then back off alittle.
    Just kidding.

    Dewayne
    Dewayne Thomas, Jun 8, 2007
    #9
  10. Dewayne Thomas

    RobV Guest

    Dewayne Thomas wrote:
    > On Fri, 8 Jun 2007 17:16:43 -0400, "RobV" <>
    > wrote:
    >
    >> Paul wrote:
    >>
    >> [snip]
    >>
    >>> Perhaps you could use CPUZ, to verify that the settings in the BIOS
    >>> are being used.
    >>>
    >>> http://www.cpuid.com/cpuz.php
    >>> http://www.cpuid.com/download/cpu-z-140.zip
    >>>
    >>> Compare the numbers, to the ratings for your RAM.
    >>>
    >>> The "registers dump" function, will make a text file for you, if you
    >>> ever need to copy and paste any of the info. The raw SPD EEPROM info
    >>> appears just below "Dump Module #1" etc.
    >>>
    >>> Paul

    >>
    >> Excellent suggestion.
    >>

    > Thanks, guys, I'll let the info I've gathered today cook awhile and do
    > some more investigating with a register dump. Last resort I can jack
    > the mem voltage up to where something smokes, then back off alittle.
    > Just kidding.
    >
    > Dewayne


    You're welcome, Dewayne.
    RobV, Jun 9, 2007
    #10
  11. "Dewayne Thomas" <> wrote in message
    news:...
    > On Fri, 8 Jun 2007 17:16:43 -0400, "RobV" <>
    > wrote:
    >
    >>Paul wrote:
    >>
    >>[snip]
    >>
    >>> Perhaps you could use CPUZ, to verify that the settings in the BIOS
    >>> are being used.
    >>>
    >>> http://www.cpuid.com/cpuz.php
    >>> http://www.cpuid.com/download/cpu-z-140.zip
    >>>
    >>> Compare the numbers, to the ratings for your RAM.
    >>>
    >>> The "registers dump" function, will make a text file for you, if you
    >>> ever need to copy and paste any of the info. The raw SPD EEPROM info
    >>> appears just below "Dump Module #1" etc.
    >>>
    >>> Paul

    >>
    >>Excellent suggestion.
    >>

    > Thanks, guys, I'll let the info I've gathered today cook awhile and do
    > some more investigating with a register dump. Last resort I can jack
    > the mem voltage up to where something smokes, then back off alittle.
    > Just kidding.
    >
    > Dewayne

    There is a separate isue, that has not been mentioned. Going to four
    memories, also increases the loadings on the actual 'signalling' lines.
    Historically (for instance), on the earlier AMD 64 chips, it was common to
    find that memories that would run 'cas 2', with just two units fitted, had
    to have the timings slowed to cas 2.5, when all four slots were used (on
    these chips the memory controller is part of the processor), or the actual
    memory clock rate had to be dropped from 400MHz, to 333Mhz. On latter
    processor chips this was improved. Now on your board, the memory
    controller is part of the motherboard, rather than the processor, but
    similar loading problems, do sometimes appear. A google search on 'running
    with all four slots full', will find literally tens of thousands of posts
    about this, with a huge number of different motherboards. Historically,
    this was why 'server' motherboards, supporting a lot of RAM slots, used
    'registered' memory (where a buffer is present on the memory module
    itself). The 'downside' of this, is that the buffer itself slows the
    memory performance a little, but it was essential on boards which had more
    RAM slots ...
    You may well find, that you have to lower the actual memory clock rate a
    little to get the system to work with all four slots filled.

    Best Wishes
    Roger Hamlett, Jun 9, 2007
    #11
  12. Dewayne Thomas

    DaveW Guest

    Most boards running in 32 bit mode that attempt to run all four RAM slots
    run into timing instability. The recommended way to get 2 GB of memory in
    such a case is to run 2 x 1GB sticks. Or switch to 64 bit OS.

    --
    ---------------------
    DaveW
    "Dewayne Thomas" <> wrote in message
    news:...
    >
    > I just put a system together using an ASUS P5B-VM with an Intel Core 2
    > Duo 6400 CPU. I wanted to use 2 GB memory (4 sticks of 512MB Kingston
    > DS) as listed in the manual as qualified memory for this MB. The
    > system runs normal and stable with 1 GB mem, but with 2 GB, all four
    > mem slots filled, it's unstable as hell and fails memtest big time.
    > Using the settings listed on page 2-19 of the manual in all various
    > combinations makes no difference. I left the mem & CPU voltages in
    > auto as I really don't have a good feel for the impact they would have
    > on the system if I imput something wrong.
    >
    > I have Win XP installed and it runs fine with 1 GB memory. I installed
    > a ATI X 1950 Pro express 16 card in it but it ran fine with the
    > onboard video also.
    >
    > Any one running this same MB with all mem slots filled, or have any
    > suggestion on why the board wont handle 2 GB mem>
    >
    DaveW, Jun 9, 2007
    #12
  13. Dewayne Thomas

    DRS Guest

    "Dewayne Thomas" <> wrote in message
    news:

    [...]

    > Thanks, guys, I'll let the info I've gathered today cook awhile and do
    > some more investigating with a register dump. Last resort I can jack
    > the mem voltage up to where something smokes, then back off alittle.
    > Just kidding.


    Never exceed the RAM manufacturer's maximum voltage spec. RAM is too easy
    to fry. With four sticks you'll probably need to run the RAM at its maximum
    voltage (DDR2 max will probably be around 2.1v but check the manufacturer's
    web site *first*) and also increase the voltage to the Northbridge
    (typically from about 1.2v to about 1.4v).
    DRS, Jun 11, 2007
    #13
  14. Dewayne Thomas

    victor Guest

    "Robv" <> wrote in
    alt.comp.periphs.mainboard.asus:

    > Dewayne Thomas wrote:
    >> I just put a system together using an ASUS P5B-VM with an Intel
    >> Core 2 Duo 6400 CPU. I wanted to use 2 GB memory (4 sticks of
    >> 512MB Kingston DS) as listed in the manual as qualified memory
    >> for this MB. The system runs normal and stable with 1 GB mem, but
    >> with 2 GB, all four mem slots filled, it's unstable as hell and
    >> fails memtest big time. Using the settings listed on page 2-19 of
    >> the manual in all various combinations makes no difference. I
    >> left the mem & CPU voltages in auto as I really don't have a good
    >> feel for the impact they would have on the system if I imput
    >> something wrong.
    >>
    >> I have Win XP installed and it runs fine with 1 GB memory. I
    >> installed a ATI X 1950 Pro express 16 card in it but it ran fine
    >> with the onboard video also.
    >>
    >> Any one running this same MB with all mem slots filled, or have
    >> any suggestion on why the board wont handle 2 GB mem>

    >
    > Anytime you add memory, that additional memory draws current,
    > making the total load of the memory voltage higher. The fix is
    > simple: go into the BIOS and increase the voltage for the memory.
    > Increase by one step, test the system and if it is not stable,
    > increase the voltage again. Repeat till you have stability,
    > although you shouldn't have to go too far to fix the problem.


    If your pc draws more current, still the voltage should stay stabilized
    at 1.8V. I'm using 4 sticks of 1GB each on P5B Plus whithout any
    problems.

    If the voltage collapses because of drawing more current, the power
    supply is insufficient.


    --
    regards, victor
    victor, Jun 11, 2007
    #14
  15. Dewayne Thomas

    mr deo Guest

    > If the voltage collapses because of drawing more current, the power
    > supply is insufficient.
    >
    >
    > --
    > regards, victor


    not saying your wrong, just curious ;)..
    isnt all of the power for the ram driven from the motherboard itself?..
    (I know the Power comes from the PSU to the MOTHERBOARD.. but I wasnt sure
    how much filtering/rectification took place on the mobo)
    mr deo, Jun 12, 2007
    #15
  16. Dewayne Thomas

    victor Guest

    "mr deo" <> wrote in
    alt.comp.periphs.mainboard.asus:

    >> If the voltage collapses because of drawing more current, the
    >> power supply is insufficient.
    >>
    >>
    >> --
    >> regards, victor

    >
    > not saying your wrong, just curious ;)..
    > isnt all of the power for the ram driven from the motherboard
    > itself?.. (I know the Power comes from the PSU to the
    > MOTHERBOARD.. but I wasnt sure how much filtering/rectification
    > took place on the mobo)


    A chain is a strong as the weakest link.


    --
    regards, victor
    victor, Jun 12, 2007
    #16
  17. Dewayne Thomas

    victor Guest

    "mr deo" <> wrote in
    alt.comp.periphs.mainboard.asus:

    >> If the voltage collapses because of drawing more current, the
    >> power supply is insufficient.
    >>
    >>
    >> --
    >> regards, victor

    >
    > not saying your wrong, just curious ;)..
    > isnt all of the power for the ram driven from the motherboard
    > itself?..


    Yes, but the MB cannot increase the power that the PSU delivers.

    A chain is a strong as the weakest link, in this case the PSU.


    (I know the Power comes from the PSU to the
    > MOTHERBOARD.. but I wasnt sure how much filtering/rectification
    > took place on the mobo)





    --
    regards, victor
    victor, Jun 12, 2007
    #17
  18. On Sat, 9 Jun 2007 15:43:33 -0700, "DaveW" <> wrote:

    >Most boards running in 32 bit mode that attempt to run all four RAM slots
    >run into timing instability. The recommended way to get 2 GB of memory in
    >such a case is to run 2 x 1GB sticks. Or switch to 64 bit OS.


    Well I tried the 2 x 1GB sticks and memtest checks them as OK, but
    boot to the operating system and video errors start. Streaks across
    the screen. then screen junping. I tell you I have had it with this
    board. The video card runs solid in other machines. Any one have a
    suggestion on a ASUS intel MB thats running solid with 1 GB sticks in
    two or four slots. Oh, bye the way, with the 2 GB memory ,(1 GB sticks
    in two slots) no settings or combination of settings available in the
    BIOS had any effect on the stability of the system. Any way, thanks to
    all hands that offered suggestions and recommendations, Appreciate it.

    Dewayne
    Dewayne Thomas, Jun 13, 2007
    #18
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