I'm yet another guy suffering from bad quality coils on my mainboard. It seems to be heat-related coz it only happen when the coil gets hot.
Hot, huh? So i thought, why not add a heatsink?
So i got a ~40mmx40mm (removed from a spoil i740) heatsink and placed it so that it touches the coil at one end. I didn't use thermal compound for this, but judging from the temperature of the heatsink i can be positive that it is working. But, after a certain temperature is reached the whine resumes.
So i added a 2600rpm 80mm fan (couldn't find my 40mm fans). This combo worked out; previously i tried fan only and it failed.
BTW this com is no where near quiet, but the coil whine is really irritating.
Will try passive cooling with a P4 1.8Aghz stock heatsink.
Guys, try this out if your coil-whine problem is heat-related.
Update: Okay, P4 heatsink up and running (not really coz it is passive). Aided by the fan from the PSU this is gonna cool a lot considering it being bigger than the CPU heatsink. I think the sheer weight of the heatsink alone can suppress the coil whine already.
Put the 40mm heatsink on another coil suspected of slight coil whine.
2nd update: Thanks to low airflow in the case, the P4 heatsink still gets too hot after a while. Trying it with 5Ved fan (quite quiet actually) now.