What makes a good heatsink?
Does it matter the material, size, how tall, how seperated the fins are? I wan't to replace my heatsink on my Beige G3 for overclocking. I found one lying around from an old comp. It fits the clip so it will work, but will it be better at dissipating heat than the stock. The "new" one is taller and a bit heavier.
Comments
Make sure you use a good thermal paster (with silver)for helping conduct/transfer the heat from the CPU to heatsink.
If you have room then put on a heatsink and fan.
See the overclocks or www.xlr8yourmac.com websites for loads of info on cpu cooling.
Dobby.
I just woke up, so I hope this makes sense.
As somebody else pointed out, the first thing you need to do is to ensure that there is a good interface between your source (in this case the CPU) and the heatsink itself. The easiest way to do this is via thermal paste, which is similar in appearance to toothpaste.
The heatsink itself should be made of a material that heats up as quick as possible. Aluminium is the standard choice, but copper is better.
The heatsink itself should have an extremely high surface area compared to its mass. The more surface area ? the easier it is for the heatsink to transfer the heat energy in to the surrounding air (again via conduction). This is why heatsinks are machined. Every time you machine a groove in to the heatsink, you increase its surface area whilst reducing its mass. Hence heatsinks that have had extensive machining tend to have a greater surface area.
The best heatsinks of the lot are actually manufactured from thin sheets of copper or aluminium which are then bonded together. If you look at the heatsink in a 1.42GHz MDD G4 or the G5s you'll see this sort of construction used. There's a hell of a lot of surface area there and not a lot of weight.
Fans are good because they ensure that 'fresh' air is contantly absorbing energy from the surface of the heatsink before being pushed away and replaced by more 'fresh' air.