A7N8X wont work at 200MHz FSB ?

Discussion in 'Asus' started by Richard Whitcombe, Dec 14, 2003.

  1. Has anyone come across this problem or a solution:

    Ive got an A7N8X deluxe motherboard (revision 2), running the latest BIOS.
    I've just bought PC3200/400MHz 512mb of Infineon RAM and an XP3200 CPU.

    The board has been running an XP2000 system well for a while with no
    stability issues.

    After fitting the XP3200 cpu the PC is not stable at 200MHz FSB at all -
    Windows BSODs on boot, my boot CDs complain about random files not found and
    so on.

    The only way i can get the system stable is by reducing the FSB to 180MHz -
    anything else has blue screens and other issues.

    According to the asus site the board SHOULD support 200MHz FSB with the
    latest bios and for what its worth, i have 2 x A7N8X boards here and both
    have an identical problem.

    I dont have another stick of RAM to test and a bit loathed to buy some in
    case that isnt the problem.

    Ive tried uping the CPU core to 1.7v but it makes absolutely no difference.

    Anyone got any suggestions or ideas why this isnt working ?
    Richard Whitcombe, Dec 14, 2003
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  2. Richard Whitcombe

    Mark Guest

    What speed memory are you running?
    Mark, Dec 14, 2003
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  3. As stated above,

    Its Infineon PC3200 (400mhz) memory bought brand new yesterday.
    Richard Whitcombe, Dec 14, 2003
  4. Richard Whitcombe

    Ed Guest

    Ed, Dec 14, 2003
  5. Richard Whitcombe

    Bill Guest

    I haven't ran into that problem but what I've got is the same
    motherboard with an XP2500, frontside buss set to 200 and multplier set
    to 11.5.
    Sandra reports it as being an XP3200, this has been running daily now
    for four months with no problems, bios temp reports the processor as being
    44 degrees C
    Bill, Dec 14, 2003
  6. Richard Whitcombe

    Bill Guest

    You might also mention what your latency settings are.

    Bill, Dec 15, 2003
  7. Richard Whitcombe

    Clark Kent Guest


    When I first installed my mobo, I had exactly the same situation for the
    first couple of weeks while I checked it out with 512-meg of Cosair 3200

    It ran fine with no problems, but I did set it back to 166 FSB since that
    seemed fast enough for my purposes. I still have not had any problems. I
    can capture video for hours with no dropped frames.
    Clark Kent, Dec 15, 2003
  8. Richard Whitcombe

    dgk Guest

    On another topic, what is your VCore voltage? I'm running at 1.725 (I
    think) and was wondering how high I can go.
    dgk, Dec 15, 2003
  9. Not good form to reply to own post but ive done some more experimenting.

    Altering VCore and the DDR voltages have made no difference.

    Ive run Memtest86 with the following results:

    FSB Speed / Ram Speed = Result

    181/181 = Pass, no errors
    200/200 = Memtest locks up on 1%
    200/150 = Crash on 0% (unhandled exception)
    167/200 = Computer fails to post. CMOS reset needed
    190/190 = 2207 errors, all on test 6, First error is on 459.3mb and ALL the
    others are above this.

    No obviously common trends there to hint at the problem unfortunately.
    Richard Whitcombe, Dec 15, 2003
  10. Richard Whitcombe

    Jim Guest

    Check the northbridge cooling. I have a rev 1.06 board that does upto
    about 185 mhz fsb any more results in memory errors. The fast the FSB the
    higher the error rate. If I put a big fan to the northbridge heatsink I can
    go above the 200 mark without problems.

    Maybe your heatsink didnt bond well or something. Do the rev 2 boards use
    a fan for northbridge or just a sink ?
    Jim, Dec 15, 2003
  11. Just a heatsink on the northbridge but i do have a 80mm fan blowing directly
    onto it so heat shouldnt be an issue. The CPU heatsink is definately on
    correctly - ive removed and replaced it 3 times and using MBM as a temp
    monitor shows no real danger of overheating.

    More and more im thinking that the board just doesnt like my brand of RAM.
    Richard Whitcombe, Dec 16, 2003
  12. Richard Whitcombe

    Ed Guest

    No fan, just a big HS which is good, nothing to break. ;p
    Ed, Dec 16, 2003
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