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1400(133) changing multiplier.

Discussion in 'AMD Thunderbird' started by Apollo, Mar 18, 2005.

  1. Apollo

    Apollo Guest

    Hi there,

    I have replaced an 850 Duron with an Athlon 1400(133), mainly
    because it was free. I did realise at the time that it would only
    run at 10.5 x 100 on my Asus A7VI-VM.

    As this mobo has no multiplier control and is not stable above
    103MHz FSB, can I alter the multiplier to 12.5 by altering the
    bridges to get 1288MHz, (or to 14 if possible).

    Anyone got any links to show what bridges to alter to get a little
    bit more out of this chip.

    Apollo, Mar 18, 2005
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  2. Apollo

    Chuck Guest

    You might want to check and be sure your memory is PC133 , the thunderbird
    1400 c, which is the chip you have, runs on a 10.5 X 133 bus normally, if
    it's defaulting to 1050 (10.5 x 100) it could be the memory, or you need to
    manually lock the FSB to 133.
    Chuck, Mar 18, 2005
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  3. Apollo

    Wes Newell Guest

    Closing the four L1 bridges will unlock the multipliers so you can control
    it externally with either MB jumerps, the bios, or using the pinmod. The
    L3 and L4 bridges on the cpu control the default multiplier and you could
    just set them to 12.5, but if you unlock the cpu and use the pinmod you
    may be able to use the upper multipliers using the pinmod to get up to a
    24x multiplier. This would depend on whether or not the 5th multiplier bit
    is used with the tbird core. If it used, there's no bridges for it and it
    would have to be set high via the pinmod. It's pin AJ27 on the cpu/socket.
    Even if it isn't used, unlocking the cpu would at least let you set a 12.5
    multiplier with the pinmod. It's also possible that the L1 bridges are
    already closed on your cpu. Some 1400's were shipped that way. If not,
    it's still a lot easier to close the l1 bridges than it is to both cut and
    close bridges on the L3/L4 bridge set. And to go from 10.5 to 12.5 only
    requires 2 pieces of wire, since only 2 bits change. You can also go to a
    13.5 multiplier with only 2 pieces of wire (if the 8x mutiplier bit is in
    the cpu).


    If you just have to do it on the cpu, this should help.

    Wes Newell, Mar 18, 2005
  4. Apollo

    Wes Newell Guest

    I also forgot to mention that there is a jumper mode setting for a 133Mhz
    FSB. And, it may work if it sets the proper divider. Worth a try.
    Wes Newell, Mar 18, 2005
  5. Apollo

    Apollo Guest

    Hi Wes,

    Thanks for the replies, I'll have a look at links later. I've
    already tried it jumpered to 133, it wouldn't boot, tested at
    various speeds and anything over 103MHz fails on prime95. The
    memory runs fine at 133MHz (memtest86 done), it just seems like a
    restriction of the chipset.

    The chip is locked, the bios and mobo have no multiplier controls,
    that I could find that is. So I should close the L1 bridges and
    use the pinmod?

    Thanks again Wes
    Apollo, Mar 19, 2005
  6. Apollo

    Chuck Guest

    It's not the processor or your motherboard that's the problem, it's the
    memory. it isn't capable of running at 133 mhz so it's forcing the
    motherboard to default to 100.
    Chuck, Mar 19, 2005
  7. Apollo

    Gordon Abbot Guest

    Not on my MB. I checked Tom's Hardware and it cannot be jumpered from
    100 to 133 even though there is a jumper there. It was the way the board
    was made. Wes is right.

    Gordon Abbot, Mar 19, 2005
  8. Apollo

    Wes Newell Guest

    Well it was worth a try. I saw one review of the board that said it used
    a KM133A instead of KM133, so i wasn't sure if 133Mhz would work or not.
    I'd start with that. It's the easiest way and you can just use a pencil to
    close the bridges to test it. And at a minimum you'll be able to get a
    12.5 multiplier. If you decide to permanately close the L1 bridges, use
    conductive paint or something. While the pencil will work it's not very
    reliable. I did a duron with one and it lost connection on 1 or 2 bridges
    after some time.
    Wes Newell, Mar 19, 2005
  9. Apollo

    Chuck Guest

    Never said he was wrong, I didn't know the motherboard in question is
    limited to a 100 mhz bus. I just checked it out on the Asus website, and
    that particular board isn't compatible with Thunderbird 1400 C (10.5*133)
    processors, it only works with the 1400 B (14*100), which is quite weird
    since it allows to manually raise the FSB to 133 in the BIOS. He may have to
    set all his memory timings to the absolute minimums to do so though, no
    Optimal, or turbo mode etc.
    Chuck, Mar 19, 2005
  10. Apollo

    Wes Newell Guest

    The problem is the KT133, or in this case the KM133 chipset. Even though
    the bios of my old KT133 chipset board list FSB speeds all the way up to
    147MHz, they didn't work. The KT133A chipset fixed that. I wasn't sure if
    it was fixed in the KM133 or not. That's why I asked him to try it.
    Apparently it isn't. Not having tested the upper multipliers of the
    Thunderbird core cpu, I'm not sure if it has the 5th multiplier bit to
    allow multipliers up to 24x. It doesn't have an external bridge for the
    5th bit like the XP's do but it still may be a valid bit inside the cpu.
    If it is, then unlocking the cpu and using the pin mod would give him
    access to all the multipliers up to 24x. Of course 14x is probably as high
    as he'd want to set it, although uping vcore to 1.85v and 15x might work
    too, but I think they were pushing the core at 1400MHz even though some
    have claimed to get over 1500Mhz from an Athlon 1000 tbird. I know I got
    over 1300 or 1400Mhz easily out of mine, but don't recall which it was and
    that was on the old Kt133 chipset board limited to about 116MHz FSB. That
    was over 2 years ago so don't recall specifics.
    Wes Newell, Mar 20, 2005
  11. Apollo

    Apollo Guest

    Hi Wes and everyone else who replied,

    Just to clarify;
    The FSB control in the bios only goes to 110MHz, it can be
    jumpered to 133MHz but is only stable at 103MHz maximum. The
    memory is definitely running at 133MHz and is stable.

    I'm going to try closing the L1 set with a pencil, but I think
    I'll have to fill them first, because the cuts/burns look too
    deep. Can I just use car body filler or something else like that
    to fill them?

    You're right Wes, the KM(T)133 chipset was released to run the
    memory at 133MHz but the FSB was only stable at 100MHz and so the
    speeds are set separately. The KT133a was the next release with
    both FSB and memory bus being stable at 133MHz.
    Apollo, Mar 20, 2005
  12. Apollo

    Wes Newell Guest

    Wait a minute, I wasn't aware of any tbird 1400's produced with organic
    packaging. What's the part number on the cpu and how many L1 bridges do
    you see 4 or 5? The 1400 tbird should be a ceramic package and does not
    cut down through the ceramic material. The part number should start A1400
    if it's a tbird, and AX1400 if it's a palomino core XP. On XP's with
    organic packaging I used super glue to fill the laser cuts. On ceramic
    parts you should never have to fill anything ever.
    Wes Newell, Mar 20, 2005
  13. Apollo

    Apollo Guest

    I don't have the system here at the moment, please bear with me it
    might take a few day but I will post back with the codes.

    Apollo, Mar 20, 2005
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