Mosfet Cooling Confusion

[PiMpShiN]

I understand that may people that overclock (especially the NF7 users) cool their mosfets to keep their voltage steady. but what i dont understand is why adding heatsinks is a necessity. Ive seen people attach ramsinks cpu, heatsinks, and even water blocks to cool their mosfets.

how is this method effective in cooling the mosfets. a piece of metal (being the heatsink) bonded to the plastic mosfets cool them? if it was like a core where they're both a type of metal i can understand but how can heat be transfered from pastic to metal.

what made me confused about cooling the mosfets was when i see people putting tiny heatsinks such as these on them and its supposed to drop the temp and allow it to give a steady flow of voltage. Im just a little reluctant to believe how this works.

anyway im not trying to say thats its all garbage and it doesnt make any sence or anything, im even planning on doing it as well. I just want to know if this is really working.

 

[Dermen]

Heat will transfer from something to anything cooler that it is in contact with. It doesn't matter that its plastic. Heat transfers from every kind of material. Some are just more effiecent than others.

Have you ever touched something made of plastic and felt that it was warm? That is heat transfering from the plastic to your hand.

 

[dalilman52]

Heat will transfer from something to anything cooler that it is in contact with. It doesn't matter that its plastic. Heat transfers from every kind of material. Some are just more effiecent than others.

Have you ever touched something made of plastic and felt that it was warm? That is heat transfering from the plastic to your hand.

lol...so condescending...but anyways, like i told u, if u cool the thing that regulates the voltage, then u would be getting more stable voltages...even possibly letting u OC even more

 

[Agent_Mull]

Also, is the core a metal? i thought it was silicon, or plastic.

 

[PiMpShiN]

dalilman tomarrow i need to use your alumina epoxy and im going to dremel those heatsinks that we got yesterday.

 

[PiMpShiN]

oh and we need to think of a way to cool my cpu. i cant get to 2.5 because my temps get to high. maybe a fan duct or something.

 

[Paxmax]

cooling mosfet.

The best way to cool those mosfets are cooling their underside.
The mosfets get most of their cooling from the motherboard traces, and some heat are ofcourse discharged through radiation and convection on top.

Sometimes the top part is made from a ceramic material but most of the times it's made from glassfiber reinforced plastic.
The ceramic har slightly better heat transfer capabilities.

It will help to effectively cool the topside too, although it will be much more efficient to cool the bottom.

 

[CCW]

Paxmax, you beat me to it, it is actrually the underside of the MOSFETs that create the most heat and heres a guide, published here at Overclockers a little while back, November I think:
http://www.overclockers.com/tips1115/index.asp

Craig

 

[PiMpShiN]

well when i tough the mosfets i barely feel any warmth at all. but just to be safe i put a 92mm fan blowing on them. would that be good enough?

and ccw the link doesnt work.

 

[CCW]

Link works for me

 

[Diggrr]

Right now I have mine cooled by an athlon heatsink that had it's side fins cut off to make it narrow enough to fit all six mosfets, using arctic alumina adhesive. Works fine, voltages much more stable now.

However, in the future I plan to just solder 1 1/2" x 1/2" tabs of copper flashing to the solder tabs that stick out from the end opposite the contacts. That's a solder point, as most are stuck to your boards using solder there (pre-tinned).

I'm not going to connect the tabs together, because I don't want to get into grounding issues between different voltage mostfets, but I think those small tabs would do just as good as my big heatsink, plus be easily removable for possible rma should something other than what I've modified crap out.

I can solder like nobody's business, so that's no problem. If you can't, find something to practice on (alot) first.
Also, I wouldn't work on the mobo with any power still on, as they could ground you and make a (+) touch elswhere hurt! After all, they are an electrical connection to your mobo's circuitry.

Have a great one!


*edit* By the way, anyone have a clue as to why even a psu that comes free with a $25 case has large heatsinks on it's mosfets' backsides, while a $150 motherboard does not? Someone needs to get a clue. (abit, asus, shuttle.....)

 

[DaWiper]

Cooling mosfets are not anything new... My mobo even comes with mosfetheatsinks from factory. Try look into a audio-amplifier. The heatsinks used there to cool the mosfets/fet-transistors makes even the most extreme cpu heatsink look like a wanna-be.

 

[CCW]

Cooling mosfets are not anything new... My mobo even comes with mosfetheatsinks from factory. Try look into a audio-amplifier. The heatsinks used there to cool the mosfets/fet-transistors makes even the most extreme cpu heatsink look like a wanna-be.

...and it is the only nForce 2 board that comes with them as stock. However, in the times of old when processors took a greedy 5 volts to run, MOSFET heatsinks came on everyboard.

Craig