P4PE Jumperfree mode?

Discussion in 'Asus' started by Dan B, Feb 25, 2007.

  1. Dan B

    Dan B Guest

    Hi all,

    I am thinking about playing around with overclocking my 2.4 P4 (533Mhz) on
    my ASUS P4PE, but I cannot find how to put the motherboard in Jumperfree
    mode. The manual refers to it, but there is no explanation. I know it is
    usually a "JEN" jumper, but I can't find one on my motherboard.

    I am running and old version 1002 BIOS, as I have had no issues with this
    motherboard, so I am thinking maybe it was added later in the BIOS, and
    maybe there is no jumper. The multiplier is grayed out in the BIOS, even
    when I set to manual mode.

    Any ideas?
    Dan B, Feb 25, 2007
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  2. Dan B

    DaveW Guest

    I have that motherboard. There are no jumpers. It's all adjusted in the
    DaveW, Feb 25, 2007
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  3. Dan B

    Dan B Guest

    Thanks Dave.

    OK. When I set it to manual, the BIOS then allows me to adjust the CPU
    external frequency. The CPU multiplier is still grayed out. I presume then I
    have a "locked" processor, and that is why I cannot change the multiplier?

    Dan Braasch

    Dan B, Feb 26, 2007
  4. Dan B

    Paul Guest

    Unless the processor is an Intel ES (Engineering Sample), it will be
    locked. To overclock, you raise the FSB, and the core rises in proportion,
    as well as the memory. To prevent the memory from going over spec, you
    turn down the memory, to the next lowest setting.

    Say you have FSB533, and some PC2700 memory. The memory is rated at
    DDR333. Say the memory is already set at DDR333. So, you set the memory
    to the DDR266 setting. (FSB533 is 133MHz CPU clock times four, to get
    the FSB transfer rate.)

    If you now raise the clock from 133MHz to 166MHz, the core frequency
    will increase by Fcore*166/133. But the memory will also be increased
    in the same way. So it would go up by DDR266 * 166/133 or DDR332. So
    now the memory is still just within spec. If we hadn't turned down the
    memory, and left it at DDR333, the memory would be DDR333 * 166/133 = DDR416.

    The Asus provided overclocking information for the board, says it would
    do up to FSB800, but by doing so, you are limited to one stick of
    memory at DDR400. So if you plan on cranking the memory bus very
    high, you have to think a bit about how many sticks you can manage
    to run at high speed. Turning down the memory clock setting a bit,
    while you establish how high the CPU will overclock, will allow you
    to determine the CPU limit, and then you can do some separate
    experiments with the memory subsystem.

    Also of note, it looks like your motherboard has an AGP/PCI lock
    function. Notice that you can set it to "Manual" and select 66.66/33.33
    for the AGP and PCI clocks. By doing that, that will prevent hard drive
    corruption caused by overclocking the IDE interface. You
    should do a bit of Googling, to find out more about whether the
    AGP/PCI lock really works on your motherboard or not. You have to
    be careful with that function, because sometimes it doesn't work as
    expected, and you really need to find confirmation that it works
    correctly, somewhere.

    In terms of overclocks, you work in tiny increments, to make it
    easier to detect the limits. For example, it may sound strange,
    but if you are at 133MHz now, you could go up in steps of 5MHz at
    a time, and see how it goes. My guess is you'll get to FSB640 or
    so, so it should take you about 5 or 6 tests to get there. In the
    case of my own machine (not a P4PE), increasing Vcore didn't really
    help me a lot, and it appears my motherboard is letting me down. My
    machine "hits a wall", once I get to a certain level of overclock.

    In terms of test procedures, I recommend disconnecting your
    regular disk drive, and cook up another kind of test. I have
    a Knoppix and a Ubuntu CD, and those are "read-only" and bootable
    disk images. I apply an overclock in the BIOS, and set the
    CD as the boot device. If icons start to disappear from the Linux
    desktop, that tells you the machine is overclocked too high :)
    You can also see a variety of error messages, as the machine is
    booting. Using a Linux boot CD, is a lot safer than messing up
    your Windows boot disk, while in some unstable overclock
    situation. If you don't have high speed Internet, to download
    a Linux distro, you can also do a clean install of Windows on
    a spare disk, and use that as your sacrificial boot disk.

    Paul, Feb 26, 2007
  5. Dan B

    Dan B Guest

    Thanks for the detailed post, Paul. Very helpful.
    Dan B, Feb 27, 2007
  6. Dan B

    Dan B Guest


    I successfully overclocked my P4PE with 2.4G P4 to 167 (668) FSB, 334 PCI.
    Anything above that I started seeing noticeable temperature increases in the
    CPU. The AGP/PCI locking worked fine. So I now have a 3.0G P4! Been running
    like this for 6 days now, just as stable as before overclock.

    So I decided to tackle my daughter's ASUS TUSL2-C with P-III Tualatin 1.2G.
    I brought both the FSB and memory bus up to 150, and the PCI is at 37.
    Everything is running stable there, too. If I tried to lower the memory
    clock to get more out of the CPU, it didn't like it much. So I experimented
    a bit, and it has been running stable at this setup for 5 days.

    Thanks for your input. I feel like I have 2 new PCs.

    Dan B, Mar 4, 2007
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