Zalman CNPS7700-Cu noise?

When running the fan at maximum speed, there seems to be a slight humming/howling noise coming from it. Is this normal?

don't know of this but make sure your fan isn't hitting anything.

-1cem4n

i am going to say yes I ran mine howling for a while. I used one for a few months and to keep my EE cool I ran it at full blast, which is where it becomes loud (34dB). I noticed mine made some extra noise, I figured it was a bearing So I replaced it with an xp-120 and I couldn't be happier. Better cooling, 24dB. also, check your other fans. could it be your NB fan?

It's possible because of the awkward design of the copper fins, when enough air goes by it, it makes a noise.

....or the fan can simply be off balance

I'd say the most likely culprit would be the fan not being balanced properly, although I would think that would cause more of a warbling hum that comes and goes rapidly.
I've got mine at full speed, and so far it's been dead silent so...
Make sure that there's nothing in the way of the airflow too.
A wire in the way could cause a howling/humming noise.

I have the 7000-ALCu and I have it plugged into the mobo so it is running a little faster than what the fan mate does on max, and it gives a little wisp. It definitaly isn't dead silent, maybe if it was on the lowest setting.