FrostyTech Acoustic Sampling Chamber
Standard Waveform view of a 10 second recording. Click on the headphones icon to listen to an MP3 recording of this heatsink in operation.

Sound Level Measurements: Which Heatsink is Quietest?

Listening to the actual noise a heatsink makes allows you to hear what pure numbers alone cannot get across. To further emphasize FrostyTech's reliance on cold hard facts when evaluating a heatsink, we also take noise level measurements with a sound level meter.

FrostyTech Heatsink Noise Level Measurements Noise level Decibel measurements of each heatsinks' fan in operation are taken with the aid of a sound level meter and sound isolating enclosure. The values may be higher than the mfgr's listed specs, but in this list are directly comparable to one another. Measurements are made on the dB (A) scale. Information on Frostytech's test methodology is available here.
Manufacturer:	Model No.:	*Fan Speed:	Noise Level (dBA):
Verax	Quattro 1		30.9 dB	Quiet
Zalman	CNPS7000A-Cu	low	32.7 dB
Zalman	CNPS7000B-CU	low	33.2 dB
Zalman	CNPS7000-Cu	low	33.5 dB
Zalman	CNPS9500LED (clip parallel)	low	36.2 dB
Gigabyte	NeonCooler 8-BL		42.0 dB
Coolermaster	Hyper48		43.6 dB
Dynatron	A22		44.5 dB
Zalman	CNPS7000B-CU	high	44.9 dB
Zalman	CNPS7000A-Cu	high	45.2 dB
Zalman	CNPS7000-Cu	high	45.2 dB
Ajigo	MF043-044		45.4 dB
Scythe	Shogun	high	45.9 dB
Scythe	Kama SCKK1000		47.5 dB
Thermaltake	Silentboost K8		49.7 dB
Zalman	CNPS9500LED (clip parallel)	high	50.3 dB
Gigabyte	3D-Rocket		50.7 dB
Evercool	K802-715		51.5 dB
Scythe	Samurai SCSM1000	high	51.6 dB
nPowertek	NPH K8-1		52.2 dB
Jetart	JAX801		53.5 dB
Coolermaster	Hyper6	high	54.7 dB
Evercool	Magic Cooler		55.5 dB
Dynatron	SK-V24		56.4 dB
Gigabyte	3D Rocket-Pro	high	56.7 dB
Vantec	Mach1	high	56.9 dB
EKL	V8	high	57.5 dB
Alpha	PAL-8150		58.9 dB
Coolermaster	Aquagate Mini	high	59.2 dB
AVC	Z7U3301001	high	59.9 dB
Cooljag	SFO-H	high	60.6 dB
Gigabyte	3D Cooler-Pro	high	62.5 dB
Gigabyte	3D Cooler-Ultra	high	63.0 dB
Titan	TTC-K8ATB/825/SC		63.1 dB
CoolJag	SFO-D(18SC)		64.0 dB
ASUS	Starice	high	67.4 dB
Thermaltake	Polo 735	high	68.0 dB
Thermaltake	Venus 12	high	68.1 dB
Gigabyte	G-Power Pro	high	71.9 dB	Loud
			noise level (dba)
*unless noted, for reference heatsinks with variable-speed fans only the 'high speed' (12V) fan noise measurement is included in the comparison sheet; more detailed results for the low fan speed (~5V) tests reside in each specific heatsink review.

I've included an assortment of Zalman's recent heatsinks in the noise level comparison chart so we can see how the Zalman CNPS9500 LED heatsink stacks up against the venerable CNPS7000-series. Normally, we'd only include the high speed fan measurements of reference heatsinks here... From the K8 heatsinks tested, we can see that the Zalman CNPS9500 LED heatsink is among the quietest at its lowest fan speed, and about 3dBA louder than the other CNPS7000-series coolers. At full speed, the fan produces just barely 50 dBA in our test environment.

Surface Finish Comparator Notes: Flatness and Finish

Surface finish is an important factor that we all look for when holding a new heatsink. Flipping a cooler over to see how well the base has been machined is a quick way to judge the attention to detail that was put into making it. The following test involves the use of a Surface Roughness Comparator, which offers a concise cross section common machine surface finishes.

The Zalman CNPS9500 LED heatsink has a surface roughness of approximately 8 microinches, which is considered very good. Next, let's see how this heatsink handles the heat compared to a selection of other heatsinks!