PC fan connectors

[Jonboy]

i am not saying it makes a power difference,
what i am saying is the tracks on the motherboard can cope with the odd cpu fan and smaller system/north/southbridge fans but i would not trust running the larger fans used for case cooling due to the thin tracks now used on the newer motherboards i would rather hook them up to the molex from the psu.
people dont realise electric current moves and any movement causes friction and friction causes heat why take the risk of burning a track out if you dont have to .

[zoombini]

And are you aware exactly how much current that those tracks can carry?
A 0.01" track (0.25mm) can carry 700ma without drawing a sweat, so even the thinner 0.005" ones (if they go down to that) can carry enough to cope with a case fan that takes only a few hundred milliamps & any going to a fan supply socket is going to be thicker than the thin signal ones.

[Matth]

Originally Posted by jonifen

Is that because the system could not report such a high RPM for the fan? Or is it because they're that damn loud you'd hear it not working before the PC reported it?

But I didnt know that... have a greenie.

The main reason they are not recommended for beasts like the 80mm 80CFM Delta
http://www.sidewindercomputers.com/del80ffb08123.html
is that the beast draws 0.9A instaed of the usual 0.2A or thereabouts for more normal fans.

While a copper track would need to be very thin to burn out at that level, the motherboard fan power may also be fed through a PWM switching control, on those boards that bother to implement it - users of Almico Speedfan http://www.almico.com/speedfan.php will find that while many chipsets support PWM speed control, many motherboard makers don't add the components to do the switching.