Fan header questions

Archived from groups: alt.comp.hardware.homebuilt (More info?)

Hi,

My manual for the Asus P4PE mainboard specifies the following for
connections to fan headers.

"The fan connectors support cooling fans of 350mA-740mA (8.8W max)."

The fan that I have selected for the cpu header is the Vantec (T9225)
Thermaflow which is variable speed with a maximum current draw of 260mA.

My questions are;

1) What is the significance of the lower 350mA Asus spec, above, as it
relates to the 260mA fan that I want to install.?

2) Given the appropriate selection of a fan to match the heat production
of a given cpu (in this case the Intel Pentium 3.06 533Mhz) is there any
overriding problem using a variable speed fan with a cpu (either with a
header or directly to a power supply?.

Thanks for any help you can provide.
4 answers Last reply
More about header questions
  1. Archived from groups: alt.comp.hardware.homebuilt (More info?)

    On Sat, 01 May 2004 16:23:34 +0930, Brenton Pettitt
    <dalpets@ozemail.com.au> wrote:

    >Hi,
    >
    >My manual for the Asus P4PE mainboard specifies the following for
    >connections to fan headers.
    >
    >"The fan connectors support cooling fans of 350mA-740mA (8.8W max)."
    >
    >The fan that I have selected for the cpu header is the Vantec (T9225)
    >Thermaflow which is variable speed with a maximum current draw of 260mA.
    >
    >My questions are;
    >
    >1) What is the significance of the lower 350mA Asus spec, above, as it
    >relates to the 260mA fan that I want to install.?

    The 350mA "might" be the max supported per header and 740mA the max per
    ALL headers combined. That seems about right, typical.... boards used
    support an average of 6W but that figure was expected to rise with hotter
    CPUs. The significance would then be that you had (740-260=) 480mA
    remaining potential for other fan(s). However, the Vantec, being variable
    speed, will never draw 260mA continuous, probably typical current would be
    closer to 140mA, except for.... (see below)


    >
    >2) Given the appropriate selection of a fan to match the heat production
    >of a given cpu (in this case the Intel Pentium 3.06 533Mhz) is there any
    >overriding problem using a variable speed fan with a cpu (either with a
    >header or directly to a power supply?.

    There is a very significant potential problem. The board has the "Q-fan"
    feature, making it (possibly) a redundant waste to use a variable speed
    fan since the board will vary fan speed automatically. The larger issue
    though is that (at least with older Asus boards I've had with that Q-Fan
    feature) use of a variable speed fan can, did result in the fan completely
    stopping prematurely, then not spinning up again even after CPU was
    clearly getting too hot. The solution was to either disable Q-Fan or use
    a non-variable, single-speed fan. I choose the latter and reused the
    variable speed fan for something else.

    So as I referred to above as "see below", the Q-Fan feature will further
    reduce that ~140mA guesstimation if the feature is enabled, but the
    primary issue is if the current stays HIGH enough, such that the fan never
    stalls. I"m not entirely sure why a stalled fan won't then later restart
    since "Q-Fan" is supposedly increasing current again but firsthand
    experience shows it to be a risk.
  2. Archived from groups: alt.comp.hardware.homebuilt (More info?)

    On Sat, 01 May 2004 21:12:58 +0930, Brenton Pettitt
    <dalpets@ozemail.com.au> wrote:

    >For the record the manual went on to say.........."or a total of
    >1A-2.22A (26.64W max at +12v...." I believe this to refer to all headers
    >combined since the manual heading is "cpu, chassis & power fan
    >connectors."

    yep, thats for all of them together ...

    >In regard to variable fans it seem they are the only ones that provide
    >high cfms with rpm moitoring and e.g.,the Vantec Tornado whilst it
    >provides 119cfm I don't believe I could live with 56.4db. The only
    >non-variable fan that I have found available in Oz is the the 92mm
    >Panaflow @ 56.8cfm & 40db, but diappointingly it has no rpm monitoring.

    this problem is resolvable, see my site under electronics ... :-)

    --
    Regards, SPAJKY ®
    & visit my site @ http://www.spajky.vze.com
    "Tualatin OC-ed / BX-Slot1 / inaudible setup!"
    E-mail AntiSpam: remove ##
  3. Archived from groups: alt.comp.hardware.homebuilt (More info?)

    Asus boards are known, or have been known in the past to blow the fan header
    power if you load it down with too many fans or they draw too much amperage.
    That said, it's very easy to overload their fan bus. You'll lose all the case fan
    power with the exception (usually.... hopefully) of the CPU fan power.

    Also, as has been said, your BIOS will vary the CPU fan speed/nonise depending
    on the temp.

    On Sat, 01 May 2004 16:23:34 +0930, Brenton Pettitt <dalpets@ozemail.com.au> wrote:

    >Hi,
    >
    >My manual for the Asus P4PE mainboard specifies the following for
    >connections to fan headers.
    >
    >"The fan connectors support cooling fans of 350mA-740mA (8.8W max)."
    >
    >The fan that I have selected for the cpu header is the Vantec (T9225)
    >Thermaflow which is variable speed with a maximum current draw of 260mA.
    >
    >My questions are;
    >
    >1) What is the significance of the lower 350mA Asus spec, above, as it
    >relates to the 260mA fan that I want to install.?
    >
    >2) Given the appropriate selection of a fan to match the heat production
    >of a given cpu (in this case the Intel Pentium 3.06 533Mhz) is there any
    >overriding problem using a variable speed fan with a cpu (either with a
    >header or directly to a power supply?.
    >
    >Thanks for any help you can provide.

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  4. Archived from groups: alt.comp.hardware.homebuilt (More info?)

    Overlord wrote:

    > Also, as has been said, your BIOS will vary the CPU fan speed/nonise depending
    > on the temp.

    Does anyone know if this also is true for the DFI LanParty NF2 Ultra?
    (that's the first version from last october, not the current one.
    I might be able to get a used one for cheap from a non-techie)
    Wolfi
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