CPU On NF7-S v2 Started Overheating But Fan Speed OK ?!

Discussion in 'Abit' started by Nick Boyce, Jun 17, 2007.

  1. Nick Boyce

    Nick Boyce Guest

    Here's a funny thing ... over the last 2 days my NF7-S-v2-based homebrew
    system CPU has begun overheating, after 2 years of trouble-free
    operation. The weird thing is that the CPU fan is running fine as
    reported by the BIOS "PC Health Status" screen.

    "MBProbe" always reports the CPU fan speed as zero RPM (the fan is
    rotating, so I've always assumed MBProbe can't detect the fan for some
    silly reason), and it agrees with the BIOS about CPU & system temperatures.

    System spec: Athlon XP 2600 (Barton), Akasa AK827 heatsink & fan (claims
    to be good up to Athlon XP 3400), 1Gb PC3200 RAM, FX5200 graphics
    (passive cooling), 40Gb IDE HD, 2 x 160Gb SATA HD, IDE DVD-ROM, IDE
    DVD-RW, no overclocking, aluminium case, "Hiper" 350W power supply.
    Normally runs so cool I don't even need the two case fans.

    I've made *no* recent hardware changes to the system.

    Symptoms: Five times in 2 days the CPU temperature has risen slowly (by
    about 1 degree every 3 or 4 minutes) from about 38C at system startup
    until it reached the warning temperature (60C) I have set in the BIOS,
    at which point the two-tone alarm sounded (and I shut the system down).
    I tried removing the case cover, which slowed the temperature rise
    down, but it still reached the warning temp eventually. Normally the CPU
    temp never exceeds ~48C. The CPU fan speed always has been, and still
    is, around 2600RPM.

    I haven't been working the beast any more than usual - mostly just email
    & web.

    ODDLY: today the CPU temp is hovering at around 53C - still higher than
    normal, but not getting any worse.

    UK weather yesterday and the day before that was torrential rain; today
    there's no rain, but no sun either. Nothing unusual.

    The north-bridge fan has been making a nasty noise for a few weeks, but
    I don't suppose that's relevant. [I know it's the north-bridge fan cos
    I tried disconnecting it, and the noise went away]

    I updated the system BIOS revision from 2.4 (as purchased) to 2.7 about
    3 months ago in a futile effort to resolve SATA problems when I added a
    second SATA drive (but that's another story).

    Given that the CPU fan seems to be okay, I can only think that the
    thermal paste between CPU and heatsink has somehow failed or degraded -
    but *why* ? (and Googling does not reveal anyone else reporting such a

    Can CPUs just fail all by themselves, in such a way they start
    generating more heat ?

    Or does anyone know of any other possible cause ?

    Nick Boyce
    Nick Boyce, Jun 17, 2007
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  2. Nick Boyce

    peter Guest

    I would remove the Akasa...clean it out maybe dust inbetween the fins.
    I would remove the old thermal compound from both the CPU and the
    heatsink...apply new thermal compound and re-seat.
    Then check temps............
    I also would re oil that NorthBridge fan......3in1 machine oil works
    nicely..but use sparingly and wipe off excess.
    peter, Jun 17, 2007
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  3. Nick Boyce

    Bill Guest

    Checked for processes running that you don't know about?
    Like maybe somebody has botted your pc and is rumming spam
    out of it?

    It's possible. Some types of paste dry out and lose their

    It wouldn't hurt to clean and reapply some thermal paste.

    Never heard of it. Anything is possible though.
    Yes, have you cleaned out the crud that builds up between
    the heatsink fins over time? It would be a good time to do
    it when you redo the heatsink paste.

    Bill, Jun 17, 2007
  4. Nick Boyce

    Nick Boyce Guest

    Thanks - I'll do that, though I had a good look at it when checking the
    northbridge fan, and couldn't see much crud in the fins ... this case (a
    Lian-Li) has nice filters on the air intakes.

    I'll try to do it without removing the heat sink though - it was the
    worst nightmare imaginable fitting it in the first place :( ... the
    amount of pressure I had to apply to the clamp spring thing left me in
    terror I was going to slip and damage the mobo.
    If absolutely necessary (i.e. problem keeps happening) I'll do that too.
    And indeed that's good advice too - I seem to recall someone posting the
    procedure for that here a while back (peeling the label off the spindle
    cover first IIRC).

    Thanks for the response.
    [CPU temp now up to 55C ...]

    Nick Boyce
    Nick Boyce, Jun 18, 2007
  5. Nick Boyce

    Nick Boyce Guest

    Well I'll check, but it's not likely ... I'm pretty careful, and well
    defended :) The overheating occurred more than once while I wasn't
    actually connected to the Net (I'm on dial-up) - though maybe it's
    poorly coded malware ;)
    Agreed - see previous response.

    Nick Boyce
    Nick Boyce, Jun 18, 2007
  6. Nick Boyce

    SumGuy Guest

    Good grief! Malware might do a lot of things, but cause your CPU to overheat
    is not one of them.
    Sounds like the most likely cause.
    You can set your CPU alarm threshold higher. XP processors are rated at
    something like 80 C, even if it overheats and freezes once or twice it's not
    the end of the world, and you can adjust the alarm accordingly.

    If you don't turn of the PC does the temp plateau?
    I guess it depends on you definition of "overheat". If a PC runs at 70 C
    happily, and never locks up, is it overheating? ;-)

    I would have though your's was "running hotter than usual", (unless it does
    lock up). Don't get me wrong, any abnormal behaviour requires investigation

    To my mind, overheating is when the comp no longer functions due to heat
    build up.

    just a thought. ;-)
    SumGuy, Jun 18, 2007
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