Heatsink question

[mikef208]

I understand that a heatsink conducts the heat from the CPU die and the fan is used to help disperse the heat from the heatsink. But wouldn't it stand to reason that most of the heat would be conducted to the bottom middle of the heatsink right above the die(correct me if I am wrong, i don't know for sure). If that is the case then having the motor part of the fan over the middle of the heatsink isn't the greatest idea isn't it? I mean if you offcenter it and allow the blades to be over the die, wouldn't that help dissipate the heat quicker?

 

[goshdarnindie]

I am going to give you an answer that I heard repeatedly from my college engineering profs, yes and no.

It all depends on the, oh shoot, what is it called, we'll call it the air column produced by a fan. It is conical in shape, everything in the cone is not moving as fast relative to the air outside of the cone. If the point of the cone is right above the top of the bottom (top of the bottom?) of the HS, then the fan should be centered. However, the presence of pins on the heatsink prevent any chance of that cone forming, in which case there is no ideal model.

Because of the turbulent nature of the flow, air could be pulled through the center just as well as any place, so offcentering it wouldn't do anything, but there is no way of telling.

Ok, now if we go on with our lesson in the book...

 

[mikef208]

Yes, but there is less air being pushed onto the pins in the center of the heatsink becuase of the motor being over the center, while the pins may turbualte(I don't know it sounded like a good word) the air so that it may eventually hit the center pins, not much air hits them directly, were as if you offcenter the fan more air will directly hit the center fins. Looks liek I will have to experiment.