Not sure if i was allowed to link the site i got this from so ill just post what it said on the page:
COMPARISON
Three competing products were chosen for comparison against the Vapochill Micro: A Thermalright XP-90 with a 92mm Nexus fan, the Arctic Cooling Freezer 4, and the venerable Zalman CNPS7000-AlCu. All of these fall roughly in the same price range, and they all use 92mm fans. For the Vapochill Micro and the Thermalright XP-90, the reference Nexus fan was used; the Freezer and Zalman heatsinks both use proprietary fans that cannot easily be swapped, so the stock fans were used. Data for the comparison comes from our reviews of the respective products, which are linked to above.
Two comparisons were done: One with the measured noise held close to 22 dBA@1m, and another at 17 dBA@1m. These are very quiet levels; the latter is effectively silent under most conditions.
Comparison #1
Heatsink Comparison by Noise #1: 22 dBA@1m Target
Heatsink
Noise
Fan Voltage
°C Rise
°C/W MP
°C/W TDP
--------------------------
Asetek Vapochill Micro, Nexus fan
22 dBA@1m
12
25
0.32
0.36
---------------------------
Thermalright XP-90, Nexus fan
20 dBA@1m
12
22
0.29
0.33
--------------------------
Arctic Cooling Freezer 4, Stock fan
20 dBA@1m
7
25
0.32
0.36
-----------------------------
Zalman CNPS7000-AlCu, Stock fan
22 dBA@1m
5
27
0.34
0.39
Comparison #2
Heatsink Comparison by Noise: 17 dBA@1m Target
Heatsink
Noise
Fan Voltage
°C Rise
°C/W MP
°C/W TDP
----------------------
Asetek Vapochill Micro, Nexus fan
17 dBA@1m
7
38
0.48
0.55
---------------------
Thermalright XP-90, Nexus fan
17 dBA@1m
7
25
0.33
0.38
--------------------------
Arctic Cooling Freezer 4, Stock fan
17 dBA@1m
5
31
0.39
0.45
hope that helps kinda, I really dont know why they rate the noise in sone instead of DB having a hard time trying to find a site which will tell DB without being compared to others.
I must add too i dont really notice how loud it is cause my case fans are pretty damn loud (vantec stealths).