Quiet 80mm fan for XP2500@2.2GHz/SLK800U

[TedKord]

I've been reading different forums for advice on this, and am seeing no real consensus.

I have an XP2500, multiplier@10.5, FSB@210MHz. It's got a TT SLK-800U on it, with the
60mm YS Tech fan that came with the Alpha PAL8035 that I had on my T-bird 700. It's
a bit loud.

I'd like to go to an 80mm, but rather than ask for a model/manufacturer of fan recommendation,
what do you think is the minimum acceptable airflow (CFM) I'd need from an 80mm fan as a
CPU cooler on this heatsink?

Keep in mind, I want to cut noise, but keep the CPU cool enough.

(Of course, I'd also be grateful for any thoughts on actual fan models you'd recommend)

My other noise reduction steps (completed) so far are replacing the two side 80mm fans and
the rear case exhaust fan with ones from silenx. They are quite a bit quieter than the originals.

See my rig below for all specs.

 

[SuperPickle]

I recently had my 2500+@2.3GHz with an 80mm fan. (SLK-900, but not that different than the SLK-800)
Sunon KD1208PTB2 39CFM@32dB
and/or
Panaflo FBA08A12H 39CFM@32dB

This kept the temps high in the upper 40's under load, but it was functional and stable. I would suggest a Panaflo H series over the Sunon though, as the quality of noise is different (and more pleasant to my ears) with its fluid bearings.