It IS worth lifting the fan away from your heatsink!

[Zak33]

Have messed for weeks with this, and there is no doubt, my CPU temp is lower with the fan held just a little way from the heatsink. It is also a bit quiter.

I have an SK-6 with a Delta going full blast on it. Not too bad on noise, but not quiet as a mouse either.
I have found it is best to superglue 4 bits of plastic to the fan, to hold the fan away a bit. I used the plastic cable clips that you use to nail cable to the skirting board or other bits of wood at home!

Just cut off the arch shaped bit of plastic, take the nail out (doh) and you have 4 bits of identical height plastic, make sure they line up with the corners of the heatsink, and glue the buggers onto the fan. I roughed up the fan plastic surround with emery paper first.

Then get the long clips from the package the heatsink came in, and bend them so they stick out wider, hence shortening the overall distance from the heatsink base to the bit where they go over the fan holes at the top! It also inreases the pressure on the fan.

I hope that makes sense! Any way , however you do it, get the heatsink away from the fan by about 1/3 inch.
It is cooler by about 2-3 degrees after an hour of Sandra

[Saturn]

Yes. What is happening is the fan is too close to the heatsink which results in too much back pressure and causes the shape of the blades to distort slightly. This in turn causes increased noise and lower air flow.
Remember the shrouds on the Alpha heatsinks. One of their purposes to give a few tenths of an inch spacing for the fan besides directing the airflow.

[chottoED]

i wonder when someone's gonna make a similar shroud for deltas on the sk6...
even though my case is a fairly solid and quiet one... the delta still gets on my nerves