Why the round shape for the stock P4 heatsink?

[hamsammich]

Hey, all. I have a quick question for you. I recently went from an Athlon 64 3500+ system to a P4 550 3.4ghz system on a Soltek MoBo.

I started experiencing some overly hot temps (which I know the P4 is famous for), and decided to make sure the stock thermal paste was spread evenly and properly. I shut everything down and took off the heatsink. Here's where my question comes in: why in the world does the stock Intel heatsink have a round shape where it contacts the processor? I noticed all four corners of the processor were uncovered and bare of thermal paste.

Now, I know the center of the processor is the hottest, but aren't most aftermarket heatsinks square to match most of the surface area of the processor? Don't those four corners need to be contacted by a heatsink and paste? Or, does it really make much difference at the corners?

Thanks in advance for any info on this!

:)

[Captain Newbie]

If I had to take a wild guess, I'd say it's to maximize surface area. That, and the core doesn't take up all the surface area under the IHS, if I had to guess again.

It also cuts costs.

Having a heatsink/fan assembly that contacts as close to the maximum surface area on the IHS will lead to the best possible air cooling performance.

Edit: Oh yeah, welcome to the forums! :attn:

[hawtrawkr]

i think they made it round to distribute air to all the mosfets/caps that surround the cpu. with the sink in the circular fashion it is it will allow the air to blow over the sink itself then divert said air all around to other components that get hot as well.

the reason the thermal paste looks round is because they only apply it in the middle of the sink. if you look at the majority of thermal paste manufacturers recommendation most would suggest only using a small amount in the center of the ihs since the core rests directly beneath.

[hamsammich]

Thanks for the replies! I just couldn't figure out the reasoning behind making the contact area on the heatsink round, and on top of that, having it smaller than the processor so that the processor corners arent' touched by the heatsink.

Thanks for the welcome as well! Also, I just joined the SETI/OC team, and I'm crunching away!

[aNTiChRisT]

Its because all the heat is in the centre of the chip, no real gains by covering the edges. Also, as previously said it is to help cool power management and pll clockgen chip.

~t0m