Is a copper/aluminum better than copper heatsink? NO right?

[da loser]

OK, I've seen this posted on various messageboards, here too, basically concluding that a heatsink like the alphas are better than all copper heatsinks in the same configuration. Due to the copper taking the heat away, then storing the heat in the aluminum heatsink away from the cpu, until it is released to the air.

Also I would think having a copper base would have little effect if used for a long
period, since the aluminum would eventually store up too much heat since copper would take heat away from the processor faster than alum/air. After a while, the temp of both copper/alum should be the same, so the transfer is completely dependent on the alum/air?

although the hedgehog is obviously better than the pal6035. what about an all aluminum pal6035?

Also some people seem to think the heat transfer coefficient is different depending on the materials involved, ie copper/aluminum or copper/air alum/air. I've seen people state that heat transfer alum/air is faster than copper/air, although copper/metal is faster than alum/metal

This is obviously wrong, right?

transfer coeffecients are dependent just upon the material than the differences between the materials used and of course temp differences?

The reason for a hybrid is mainly cost, and perhaps weight/surface area ratio?

 

[lifeguard1999]

If two heatsinks were built exactly the same, but one was made out of copper and the other aluminum, then the copper heatsink would perform better. Make an exact copy out of silver and it will perform better than either the copper or aluminum heatsinks.

The material that heatsinks are made of is only one factor in how they perform. The other two major factors are surface area (how many pins) and air flow (how fast the fans are).

Now, the Alpha and the Hedgehog are not made exactly the same. Thus, the Alpha with its copper base can provide slightly better cooling than the Hedgehog, even though the Hedgehog is made entirely out of copper. The Alpha PAL 6035 has 363 pins. The Hedgehog has 238. Thus the Alpha has more surface area over which to lose heat.

The reason for a hybrid heatsink is to get the best of both worlds. Aluminum is cheap, easy to work with, and provides heat transfer just slightly less than copper. Copper is very soft, expensive, and hard to work with. Copper provides a better heat transfer.

Now what I wonder, and have yet to see, is a comparison of when a heatsink is good enough. If the Alpha wins by 1 degree, but costs more, then will it really help you that much? Probably not. If it wins by 5 degrees, then maybe it will.

By the way, the heatsink tests on Anantech and Tom's Hardware are basically worthless. Look at the reviews on Overclockers.com Heatsink Reviews to see why.