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Would this be an overclocked system?

Discussion in 'Overclocking' started by David Farber, Oct 10, 2007.

  1. David Farber

    David Farber Guest

    Athlon XP3000+ M CPU in an ASRock K7VT4A+. 512Mb PC2700 ram.

    The default settings according to AMD is fsb=133MHz and a multiplier of 16
    (2128MHz).

    Would there be an advantage gained if I change the fsb to 166MHz and the
    multiplier to 13 (2158MHz)? I believe this motherboard allows you to change
    the multiplier settings. Could the increased fsb cause problems with the
    other devices on the motherboard or does the motherboard automatically set
    the correct dividers for the other components?

    Thanks for your reply.
    --
    David Farber
    L.A., CA
     
    David Farber, Oct 10, 2007
    #1
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  2. David Farber

    Paul Guest

    David Farber wrote:
    > Athlon XP3000+ M CPU in an ASRock K7VT4A+. 512Mb PC2700 ram.
    >
    > The default settings according to AMD is fsb=133MHz and a multiplier of 16
    > (2128MHz).
    >
    > Would there be an advantage gained if I change the fsb to 166MHz and the
    > multiplier to 13 (2158MHz)? I believe this motherboard allows you to change
    > the multiplier settings. Could the increased fsb cause problems with the
    > other devices on the motherboard or does the motherboard automatically set
    > the correct dividers for the other components?
    >
    > Thanks for your reply.


    Executive summary:

    Yes. There is an advantage. More FSB speed allows better memory transfer speeds.

    There is no "lock" setting or discrete frequency setting ( AGP/PCI 66.66/33.33MHZ )
    in your BIOS.

    There are four frequencies of interest.

    1) Clock feeding CPU.
    2) Clock feeding memory (usually a ratio of simple integers, times CPU clock signal)
    3) Clock feeding PCI cards
    4) Clock feeding AGP card.

    3 & 4 tend to be related to one another (AGP = 2 * PCI), so I won't treat them
    separately, and assume they are related by a factor of 2. If PCI is 37.5 MHz
    (the max useful value with no danger), then AGP would be 75MHz. The standards
    define AGP and PCI as 66.66MHz and 33.33MHz as nominal values. Values above 75MHz
    for AGP, cause problems for cards more modern than ATI 9800Pro. Older cards,
    can take clocks higher than that.

    In the clock generator chip, for older technologies (where the BIOS doesn't show
    a separate setting for AGP and PCI clocks), the PCI clock is derived from the
    CPU clock. If CPU is 133Mhz, they use a divider of 4 inside the clock generator
    chip. If CPU is 166MHz, they use a divider of 5. The "special" frequencies
    of 133MHz and 166MHz, also happen to be the values selected by the processor maker.

    Intermediate frequencies may be selected manually in the BIOS. For example, bumping
    up the 133Mhz clock to 150MHz, gives 150/4 = 37.5MHz for PCI. Therefore, for maximum
    safety on an older motherboard, you avoid frequencies between 150 and 165MHz, and the
    next useful value is 166MHz (if it works). It means that while the BIOS may offer
    a fine tuning option, there are still "zones" of frequencies to avoid. Corruption
    of your disk drive may result if you violate the rule. (Which is why, if testing
    for initial stability, I like to boot with a Knoppix CD in the CDROM drive. You
    can't hurt a CD. Knoppix is a 700MB .ISO download from knopper.net and is a Linux
    operating system.)

    The memory clock settings in the BIOS, are not absolute frequencies as such. If you
    select 133MHz for memory, and the CPU is 133MHz as well, the design probably has a
    1:1 ratio between the two clock signals. If you then bump the CPU clock manually
    to 150MHz, that should result in the memory overclocking by the same amount. A
    memory at 150MHz, is running at DDR300. When the CPU clock is using one of the magic
    values of 133MHz or 166MHz, it is also possible that the memory values will
    again read correctly. (So, in a sense, "sane" ratios exist at the magic clock
    values. Oddball values, which you can still adjust around, exist for intermediate
    settings. You can observe how this works, by using a copy of CPUZ from cpuid.com
    and make tiny changes, then observe the reported results in CPUZ.)

    So, by all means, try the CPU jumper of 166MHz. Your RAM is PC2700 or DDR333, and it
    is a perfect fit for a DDR333 setting in the BIOS. The best transfer efficiency, is
    often when the CPU and memory on these systems, is at the 1:1 ratio. So if using
    FSB266, then DDR266 might be good. (To do better on the memory, you might have to
    go to DDR400 setting, to beat the latency disadvantage, with the clock rate advantage.
    Add latency happens, when the memory bus samples need to be resynchonized to the
    FSB interface.)

    If using FSB333, then DDR333 might be good. Check that the multiplier setting you need,
    works properly while you are still at FSB266 or lower. If you are sure the multiplier
    works properly, then switch up to FSB333 and try it. If the setting doesn't work,
    try FSB266 jumper and DDR266 BIOS settings, then use the manual BIOS control to go
    from a CPU input clock of 133MHz, to 150MHz. 150MHz should be the next lowest safe
    clock choice.

    To see some of how the clock generator chip works, this is a sample datasheet.
    This clock generator is a couple generations older than the one on your motherboard.
    You can see how the PCI clock is affected by the main clock choice here. The jumpers
    on your motherboard, would go to the equivalent of the FS3,FS2,FS1,FS0 signals,
    and helps to select a "magic" value for system startup.

    http://web.archive.org/web/20041014100151/www.icst.com/pdf/ics9250-08.pdf

    There are many clock generators made by that company. To see how many, have
    a look at this list.

    http://web.archive.org/web/20041014100151/www.icst.com/pdf

    And yes, these are all aspects of overclocking.

    HTH,
    Paul
     
    Paul, Oct 11, 2007
    #2
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  3. David Farber

    David Farber Guest

    "Paul" <> wrote in message news:fekgj7$9qu$...
    > David Farber wrote:
    > > Athlon XP3000+ M CPU in an ASRock K7VT4A+. 512Mb PC2700 ram.
    > >
    > > The default settings according to AMD is fsb=133MHz and a multiplier of

    16
    > > (2128MHz).
    > >
    > > Would there be an advantage gained if I change the fsb to 166MHz and the
    > > multiplier to 13 (2158MHz)? I believe this motherboard allows you to

    change
    > > the multiplier settings. Could the increased fsb cause problems with the
    > > other devices on the motherboard or does the motherboard automatically

    set
    > > the correct dividers for the other components?
    > >
    > > Thanks for your reply.

    >
    > Executive summary:
    >
    > Yes. There is an advantage. More FSB speed allows better memory

    transfer speeds.
    >
    > There is no "lock" setting or discrete frequency setting ( AGP/PCI

    66.66/33.33MHZ )
    > in your BIOS.
    >
    > There are four frequencies of interest.
    >
    > 1) Clock feeding CPU.
    > 2) Clock feeding memory (usually a ratio of simple integers, times CPU

    clock signal)
    > 3) Clock feeding PCI cards
    > 4) Clock feeding AGP card.
    >
    > 3 & 4 tend to be related to one another (AGP = 2 * PCI), so I won't treat

    them
    > separately, and assume they are related by a factor of 2. If PCI is 37.5

    MHz
    > (the max useful value with no danger), then AGP would be 75MHz. The

    standards
    > define AGP and PCI as 66.66MHz and 33.33MHz as nominal values. Values

    above 75MHz
    > for AGP, cause problems for cards more modern than ATI 9800Pro. Older

    cards,
    > can take clocks higher than that.
    >
    > In the clock generator chip, for older technologies (where the BIOS

    doesn't show
    > a separate setting for AGP and PCI clocks), the PCI clock is derived from

    the
    > CPU clock. If CPU is 133Mhz, they use a divider of 4 inside the clock

    generator
    > chip. If CPU is 166MHz, they use a divider of 5. The "special" frequencies
    > of 133MHz and 166MHz, also happen to be the values selected by the

    processor maker.
    >
    > Intermediate frequencies may be selected manually in the BIOS. For

    example, bumping
    > up the 133Mhz clock to 150MHz, gives 150/4 = 37.5MHz for PCI. Therefore,

    for maximum
    > safety on an older motherboard, you avoid frequencies between 150 and

    165MHz, and the
    > next useful value is 166MHz (if it works). It means that while the BIOS

    may offer
    > a fine tuning option, there are still "zones" of frequencies to avoid.

    Corruption
    > of your disk drive may result if you violate the rule. (Which is why, if

    testing
    > for initial stability, I like to boot with a Knoppix CD in the CDROM

    drive. You
    > can't hurt a CD. Knoppix is a 700MB .ISO download from knopper.net and is

    a Linux
    > operating system.)
    >
    > The memory clock settings in the BIOS, are not absolute frequencies as

    such. If you
    > select 133MHz for memory, and the CPU is 133MHz as well, the design

    probably has a
    > 1:1 ratio between the two clock signals. If you then bump the CPU clock

    manually
    > to 150MHz, that should result in the memory overclocking by the same

    amount. A
    > memory at 150MHz, is running at DDR300. When the CPU clock is using one of

    the magic
    > values of 133MHz or 166MHz, it is also possible that the memory values

    will
    > again read correctly. (So, in a sense, "sane" ratios exist at the magic

    clock
    > values. Oddball values, which you can still adjust around, exist for

    intermediate
    > settings. You can observe how this works, by using a copy of CPUZ from

    cpuid.com
    > and make tiny changes, then observe the reported results in CPUZ.)
    >
    > So, by all means, try the CPU jumper of 166MHz. Your RAM is PC2700 or

    DDR333, and it
    > is a perfect fit for a DDR333 setting in the BIOS. The best transfer

    efficiency, is
    > often when the CPU and memory on these systems, is at the 1:1 ratio. So if

    using
    > FSB266, then DDR266 might be good. (To do better on the memory, you might

    have to
    > go to DDR400 setting, to beat the latency disadvantage, with the clock

    rate advantage.
    > Add latency happens, when the memory bus samples need to be resynchonized

    to the
    > FSB interface.)
    >
    > If using FSB333, then DDR333 might be good. Check that the multiplier

    setting you need,
    > works properly while you are still at FSB266 or lower. If you are sure the

    multiplier
    > works properly, then switch up to FSB333 and try it. If the setting

    doesn't work,
    > try FSB266 jumper and DDR266 BIOS settings, then use the manual BIOS

    control to go
    > from a CPU input clock of 133MHz, to 150MHz. 150MHz should be the next

    lowest safe
    > clock choice.
    >
    > To see some of how the clock generator chip works, this is a sample

    datasheet.
    > This clock generator is a couple generations older than the one on your

    motherboard.
    > You can see how the PCI clock is affected by the main clock choice here.

    The jumpers
    > on your motherboard, would go to the equivalent of the FS3,FS2,FS1,FS0

    signals,
    > and helps to select a "magic" value for system startup.
    >
    > http://web.archive.org/web/20041014100151/www.icst.com/pdf/ics9250-08.pdf
    >
    > There are many clock generators made by that company. To see how many,

    have
    > a look at this list.
    >
    > http://web.archive.org/web/20041014100151/www.icst.com/pdf
    >
    > And yes, these are all aspects of overclocking.
    >
    > HTH,
    > Paul


    I believe your executive summary really connected the dots for me. Let me
    make sure I understand this though. As long as I pick one of the preset (is
    that what you define as magic?) frequencies, the "frequencies of interest"
    take care of themselves. The tricky part is what happens when you bump the
    fsb speed a bit and all the other frequencies get bumped as well which is
    why you need to know what frequencies to avoid.

    I changed the fsb to 166, the multiplier to 13, and so far, the system is
    stable.

    Thanks for your reply.
    --
    David Farber
    L.A., CA
     
    David Farber, Oct 11, 2007
    #3
  4. David Farber

    Paul Guest

    David Farber wrote:

    > I believe your executive summary really connected the dots for me. Let me
    > make sure I understand this though. As long as I pick one of the preset (is
    > that what you define as magic?) frequencies, the "frequencies of interest"
    > take care of themselves. The tricky part is what happens when you bump the
    > fsb speed a bit and all the other frequencies get bumped as well which is
    > why you need to know what frequencies to avoid.
    >
    > I changed the fsb to 166, the multiplier to 13, and so far, the system is
    > stable.
    >
    > Thanks for your reply.


    The set of frequencies defined by the processor manufacturer, all seem to be
    a multiple of the PCI standard frequency. 133MHz, 166Mhz, and 200Mhz are
    examples. They may have chosen those frequencies, so they could use a
    simple divider to make PCI and AGP frequencies. They have other techniques
    now, for creating PCI and AGP, which allows the PCI and AGP to be "locked".
    So on more modern boards, you can dial the CPU clock in 1MHz increments,
    without having to worry about PCI and AGP. The frequencies are no longer
    "magic".

    But previous generations were not quite as flexible, and the PCI/AGP/memory
    clocks floated along with the CPU clock. And that is why there are certain
    CPU clock settings, which might not make the other bits of hardware happy.

    One reason for corrupting a disk, is the PCI clock is used to derive a
    clock for the IDE ribbon cable to the disk drive. If the IDE clock goes
    too far out of spec, that corrupts data transfer to and from the drive.
    Even SATA and PCI Express interfaces have issues like this, and there are
    some SATA motherboards, where overclocking will corrupt SATA. Even more
    recent clocking schemes, have fixed those kinds of issues, so that
    SATA and PCI Express are locked (i.e. independent) as well.

    If you changed to the CPU input to 166MHz (=FSB266), and set the multiplier
    as you liked, and CPUZ verifies that all the resulting frequencies are
    correct, you have nothing to worry about. Test with Orthos or Prime95 "torture
    test", and verify that the machine is really stable. Just booting into
    Windows is not a stability test. I put the Orthos link first here, simply
    because the interface is a little easier to understand. Orthos will run more
    than one thread for testing, and so Orthos can be used on dual core processors.

    http://sp2004.fre3.com/beta/beta2.htm (Orthos tester)
    http://www.mersenne.org/freesoft.htm (Prime95)

    Prime95 was invented to find Prime Numbers, a mathematics thing. The torture
    test option in the Prime95 program, was simply put there to verify that a
    computer about to work on finding prime numbers, was working properly. No
    sense verifying a prime number, with a computer that makes mistakes. Purely
    as an accident, overclockers discovered the testing option, and the
    Prime95 program became more popular because of that feature, than it
    did in furthering the study of mathematics.

    Paul
     
    Paul, Oct 12, 2007
    #4
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