Hi there,
Same fans and usage pattern here. While I can say that for their performance I consider them to be rather quiet and that their noise characteristics are not annoying to me, I don't consider them to be dead quiet. In fact, they are very clearly noticeable to me.
I've always interpreted statements regarding them to be quiet more along the lines of "for the power they have they don't make too much noise".
As an example of a fan which I consider to be actually dead quiet I would name the Noiseblocker Multiframe M12-S1. But then again, those are only rated at half the pressure (although almost the same CFM I think), so performance will most likely suffer (leaving out the fact that ratings do not necessarily reflect actual performance). But they really are only noticeable when I hold my ear about 10 cm up to them. And that's with nothing else running, so as soon as I turn on an HDD or another fan, the NB's are almost impossible to hear.
Haven't done any radiator testing though since I only use one NB for slight air circulation over my HDD's.
I like the SP-120's quite a bit, but I would never describe them as dead quiet on 12 V. When I take them down to 7 V I would call them very quiet and on 5 V they come close to dead quiet (at least to me
). But performance takes quite a hit with those settings.
I run a 2600k at 1.39 V along with 8 7200 rpm HDD's in Aquadrives. Usually my CPU's hottest core is somewhere between 68 and 72 deg C during folding on all cores and with normal room temps. Taking the fans down can easily increase my CPU temps by 10 degrees or more (I haven't run exact measurements and benches, but as a ballpark figure that's about right).
Even though acoustic pressure can be easily measured, noise perception is very subjective (duh
), so opinions can be expected to vary quite a bit. But yours does not seem entirely unreasonable to me.
