Back Door CPU Cooling: Iwill KK266

SUMMARY: Cooling secondary heat sources on the motherboard can reduce CPU temps.

It is a known fact that the “secondary” heat sources on motherboards are a contributing factor to a CPU’s heat load. I did a test a couple of months ago (HERE) which showed a 1-2 C benefit from cooling the Northbridge and power transistor chips by using extra fans.

I noticed on the KT133A boards that as you increase FSBs and speeds, both these areas got progressively warmer. In recognition of this, both ASUS and ABIT’s KT133A boards use active cooling on the Northbridge chip; there is nothing on the power transistors. The Iwill KK266 has no active cooling on the Northbridge chip, an omission I think should be corrected (BTW: Iwill ships this board with NO thermal grease on the greenie over this chip – a REAL NO NO! on their part).


I like the Iwill a lot and decided to actively cool both chipsets. For those of you with ABIT KT7s, the power transistor layout is virtually the same, so you can use this approach also. Not so on the ASUS.

The first part was easy: I mounted a Lasagna BGA Cooler Type A on the Northbridge. This is just a straight bolt-on job.


Cooling the power transistors was more of a challenge: I scrounged around and found an old heatsink that I proceeded to cut up to fit over all 6 power chips. Luckily they lie in a line that a heatsink can span easily, so one sink can cool the whole complex.

After cutting, I then used thermal epoxy to mount the heatsink to the chips. Be careful when you do this: Make sure that you are not touching any other parts. Best to do a “dry mount” to make sure of this.

After doing this, I noticed that CPU temps decreased by anywhere from 0.6 C to 1.3 C depending on speeds. This was without a fan on the power transistor heatsink. I did notice that after a while, the power heatsink does get warm – it’s doing its job. Mounting a fan on top is the last step and may get another degree or so off CPU temps.

All told, a fairly easy way to do some extra cooling that sure can’t hurt.

Email Joe

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