Question on AMD 64 chip and fan

Discussion in 'Computers' started by Andrew Bunk, Dec 13, 2005.

  1. Andrew Bunk

    Andrew Bunk Screenwriter

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    I'm building a PC for a friend, which includes an AMD 64 3500+ processor on a DFI Lanparty UT nF4 SLI-D motherboard. Also running a BFG 7800GT video card (just one for now) and a couple of SATA drives.

    This is the first time I've worked with an AMD processor, and I've noticed a few times that when I start up the system, the fan over the CPU heatsink is running, but once I get close to loading Windows, it will stop for a while.

    According to the hardware monitor software that came with the motherboard, when the PC is relatively idle, the CPU temp is around 26C. That seems pretty cool compared to my P4.

    My question is, do AMD chips and/or motherboards manage the CPU fan so it's not running below a certain temperature? Just trying to figure out if I should be wary of this behavior.

    Thanks in advance!
     
  2. Joe D

    Joe D Supporting Actor

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    I'm no expert, but I've never heard of a fan shutting down for a CPU, that seems very dangerous. My AMD 3000+ CPU's fan runs all the time at varying speeds.

    The AMD CPU should run cooler than a P4. But to have a fan turn off completely sounds like a recipe for meltdown.
     
  3. Andrew Bunk

    Andrew Bunk Screenwriter

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    I'll have to check if there's something in the BIOS thhat might be controlling that. I will say there's a big 120mm fan on the door pointed right at the processor that's always on.

    I'm about to put it through stress testing running World Of Warcraft at maxed out graphics for a few hours so I can see how it handles itself. I'll be keeping a close eye on the fan.
     
  4. Christ Reynolds

    Christ Reynolds Producer

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    have you actually seen the fan stop, or are you going by the monitoring software?

    yeah basically anything by amd right now will run cooler than any current offering by intel. i've never heard of a cpu fan shutting down because of it not being needed. if it is shutting down, i wouldnt worry THAT much, unless the fan shuts down at anything other than idle, as 26C is a pretty low temp, so the heatsink plus the circulating air around the case would probably prevent any damage to the cpu. i'd still look into it more, maybe you need to flash to the most current bios.

    CJ
     
  5. Andrew Bunk

    Andrew Bunk Screenwriter

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    I've actually watched it shut down.

    I did a bit more digging, and I'm thinking maybe the board is being underpowered. The case has a 500W PSU, but it's the one that came with the case (Aspire X-Navigator), and in my experience those PSU's are not as robust as a similarly rated Antec or like brand.

    Anyway, the mobo does have two connectiosn to receive 4-pin Molex power connections from the PSU, but the docs for the board only suggest it for systems running dual video cards for "increased system stability". I'm going to connect power to those and see if the results are different.

    A list of what I'm running on the system:

    2 1GB DDR400 PC3200 memory sticks
    1 DVD burner
    1 floppy
    2 SATA 120GB HD
    1 BFG 7800GT 256MB graphics card (requires six pin power connection)
    1 Creative SB Audigy2 sound card
    4 80mm fans
    1 120mm fan
    1 Front panel LCD temp readout

    Also, I replace the normal thermal solution from the processor's heatsink with Arctic Silver 5.

    Hopefully it is just a power issue.
     
  6. Mike_J_Potter

    Mike_J_Potter Second Unit

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    Your issue has nothing to do with the power supply. There is a setting in the BIOS that controls the speed, if the cpu goes below 25C it turns off and it will adjust its speed accordingly to the temp. You can change it so it will run all the time. I had the same issue with my DFI board.

    Here is some more info on the DFI forum

    http://www.dfi-street.com/forum/show...u+fan+stopping
    http://www.dfi-street.com/forum/show...u+fan+stopping
    http://www.dfi-street.com/forum/show...+fan+stopping


    Also you mentioned the 2 other connectors on the board for additional power, everything i have seen says to use them both for max stability.
     
  7. Andrew Bunk

    Andrew Bunk Screenwriter

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    Mike,

    Thanks a bunch for posting this. I was going to do some more digging in the BIOS, but it is a bit labyrinthine in there!

    I'll give this a shot tonight.
     
  8. Mike_J_Potter

    Mike_J_Potter Second Unit

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    The fan settings are under the PC health status in the bios. Just turn down the CPU temp max fan speed. You can also adjust the case fans and chipset fan if you want. Or check out dfi-street.com they have several guides for tweaking the bios, and a very good forum for dfi boards, several DFI employees post there as well. It helped make my build smooth, now I am just trying to see how high I can overclock it.
     

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