Acoustic Samples: Listen to this Heatsink!

The Akasa AK-961 heatsink should be very quiet when its fan is controlled by a Pulse Width Modulation (PWM) compliant motherboard BIOS. With a rated fan speed of between 500RPM and 3400RPM the AK-961 can alternate between very quiet and loud given the processor's thermal load.

Since we have to test with a 3-pin power connection, the Akasa AK-961 defaults to a fan speed of 3400RPM which creates a real racket (60 dBA). To listen to this heatsink in operation at its full fan speed, click on the little headphones icon below and play the sample MP3 files.

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. The fan is rotating at 3400 RPM.

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 are directly comparable to one another. Measurements are made on the dB (A) scale, lower values are best. Information on Frostytech's test methodology is available here.
Manufacturer:	Model No.:	Fan* Speed:	Noise Level (dBA):	CPU** Platform
Verax	Quattro 1	low	30.9 dB	Intel/AMD
Zalman	CNPS7000B-CU	low	33.2 dB	Intel/AMD
Scythe	Shogun	low	33.7 dB	Intel/AMD
ASUS	Starice	low	34.4 dB	Intel/AMD
Zalman	CNPS7700-Cu	low	35.1 dB	Intel/AMD
Thermalfly	F1-IACSHA	low	35.4 dB	Intel/AMD
Zalman	CNPS9500 LED	low	36.2 dB	Intel/AMD
Verax	Helado		36.3 dB	Intel/AMD
Zalman	CNPS8000	low	36.4 dB	Intel/AMD
Thermalfly	I75DUB		38.7 dB	Intel
Gigabyte	3D Cooler-Pro	low	38.8 dB	Intel/AMD
Intel	Stock Pentium D	low	40.5 dB	Intel
EKL	V8	low	41.0 dB	Intel/AMD
Gigabyte	3D Cooler-Ultra	low	42.8 dB	Intel/AMD
Coolermaster	Hyper48		43.6 dB	Intel/AMD
Gigabyte	3D Rocket-Pro	low	43.8 dB	Intel/AMD
Zalman	CNPS7000B-CU	high	44.9 dB	Intel/AMD
Gigabyte	GH-PCU23-VE	low	44.9 dB	Intel/AMD
Noctua	NH-U12		45.4 dB	Intel/AMD
Scythe	Shogun	high	45.9 dB	Intel/AMD
Intel	Stock Pentium D	high	47.5 dB	Intel
Coolermaster	Aquagate Mini	low	48.6 dB	Intel/AMD
Thermalfly	I75DUH		48.7 dB	Intel
Spire	SP601B3		48.9 dB	Intel/AMD
nPowertek	NPH-775-1		50.1 dB	Intel
Zalman	CNPS9500 LED	high	50.3 dB	Intel/AMD
Gigabyte	3D-Rocket		50.7 dB	Intel/AMD
Zalman	CNPS7700-Cu	high	50.7 dB	Intel/AMD
Gigabyte	G-Power Pro	low	50.9 dB	Intel/AMD
OCZ	Tempest		51.6 dB	Intel/AMD
Apack	Zerotherm BTF80		51.9 dB	Intel/AMD
Apack	Zerotherm BTF90		52.1 dB	Intel/AMD
Zalman	CNPS9500 AT		53.3 dB	Intel
Thermlatake	Jungle512	low	53.7 dB	Intel
Thermalright	Ultra 120		53.7 dB	Intel/AMD
Verax	Quattro 1	high	55.4 dB	Intel/AMD
Akasa	AK-960E		56.3 dB	Intel
Zalman	FS-C77		56.5 dB	Intel/AMD
Gigabyte	3D Rocket-Pro	high	56.7 dB	Intel/AMD
Zalman	CNPS8000	high	57.4 dB	Intel/AMD
EKL	V8	high	57.5 dB	Intel/AMD
Sunon	Watrubo		57.5 dB	Intel
Antazone	AS-C1000		57.6 dB	Intel/AMD
Noctua	NH-U9		58.4 dB	Intel/AMD
Coolermaster	Aquagate Mini	high	59.2 dB	Intel/AMD
Thermalfly	F1-IACSHA	high	60.4 dB	Intel/AMD
Akasa	AK-961		60.7 dB	Intel
Thermaltake	Jungle512	high	60.8 dB	Intel
Gigabyte	3D Cooler-Pro	high	62.5 dB	Intel/AMD
Gigabyte	3D Cooler-Ultra	high	63.0 dB	Intel/AMD
Evercool	PT02-9232CP		63.3 dB	Intel
Gigabyte	GH-PCU23-VE	high	65.6 dB	Intel/AMD
ASUS	Starice	high	67.4 dB	Intel/AMD
Thermalfly	I75DUB	high	68.5 db	Intel
Gigabyte	G-Power Pro	high	71.9 dB	Intel/AMD
			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. ** 'AMD' denotes compatibility with socket 754/939/940 & AM2 processors where applicable. 'Intel' denotes compatibility with socket 775 platform.

With its 90mm PWM fan spinning at 3400RPM the Akasa AK-961 heatsink generates 60.7 dBA noise. With just 5V going into the fan, noise levels hover around 36.0 dBA. This value was not recorded above because we cannot be certain it represents 500RPM on the PWM fan, as PWM fans scale speed in a different fashion. By comparison, the stock socket 775 Intel Pentium D heatsink produces about 47.5 dB at its fastest speed.

Surface Finish and Flatness

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 Akasa AK-961 heatsink has a surface roughness of approximately 63 microinches, which is considered excellent. Next, let's see how this heatsink handles the heat compared to a selection of other heatsinks!