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How to Choose a Motherboard
And Not Be Sorry Afterwards


Cooling Northbridge

I used to recommend motherboards without additional cooling devices for the northbridge, because it indicated a "correct", competently designed product. However, the tendencies are different now, and northbridge cooling is a standard. Alas... So, we should try to evaluate the efficiency of northbridge cooling system. If it exists, it should be effective: "store is no sore". What useful information can we get from its visual examination? Not that little...

I never recommend motherboards with active cooling installed on the northbridge (heatsink + fan). The source of negative information is my personal experience. Let manufacturers correct me if I'm wrong, but I don't believe that such systems use expensive and reliable fans. And a cheap simple fan will be buried in dust and fail in a year of active service. Then, you should be aware that a heatsink with inoperable fan on top is much worse than a heatsink without a fan at all. Let's conclude the topic of active northbridge cooling here...

Photo 3. It cools well... While it is working...

Preference should be given to high pin-fin heatsinks. This heatsink design without a fan provides maximum effective cooling by the air flow inside a PC case (we have already discussed why it's better when there is no fan).

Photo 4. The ideal heatsink:
clever mounting system, good high pins.

High fin heatsinks are less preferable, even when their multiple fins are narrow enough. Why? It's because the air torrents blowing transverse to the fins, will provide much worse cooling. Of course, you may reply that the air torrents will blow in the necessary direction as well. I have one question: will you study the air circulation inside your computer? You may not answer...

Photo 5. Good mounting, but the shape is not ideal.

The worst option is small flat fin heatsinks, or heatsinks with very short pins, as well as the majority of decorative solutions. I guess those who read the previous paragraphs need no explanations why. In fact, such a heatsink is a dummy by 70% (that's the mildest figure). All it can do is to compensate instant heating to a small degree, but it will not protect the chip from constant overheating.

Photo 6. Excellent, nice design element.
It has little to do with cooling.
The only good news is that it's the southbridge.

The mounting method can tell very much about the manufacturer's attitude to us. If a motherboard has special latches for the heatsink (two main varieties are shown on Photos 4 and 5 above), most likely there is thermal paste between the chip and the heatsink. In this case the latches are necessary, because thermal paste cannot glue the heatsink to the chip – it has a different task.

If there are no latches for the heatsink (Photo 7), you can be 100% sure that it's glued to the chip. 90% chances are that it's glued by an adhesive plastic tape, which transmits heat much worse than the bad thermal paste. At best it means that the cooling capacity of this heatsink is artificially reduced (because of the mounting method). At worst (which is not that rare) it means that this heatsink is a complete dummy.

Photo 7. There is no latch, so the heatsink is most likely
glued. Try to "turn" it holding it with your fingers at its sides.
If it yields a little, it's certainly glued by a plastic adhesive tape.

As you can see, even visual examination of the northbridge cooling system can tell us very much. I can only add that effective cooling generally increase the safety margin of a motherboard (though the bottleneck may be in some other place). But it won't definitely make it worse.

Vladimir Rybnikov (puree@ixbt.com)
February 1, 2004


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