Acoustic Samples: Listen to this Heatsink!

When the Zalman CNPS9500 AT heatsink powers up to its full speed of 2650RPM after about 5 seconds of running in its quietest mode, noise levels become audible (53.5 dBA) but not exceedingly loud. The 4-pin PWM fan will do this whenever it is connected to a 3-pin motherboard fan header. When a motherboard with a PWM CPU fan header is used, the BIOS takes control of the fans' speed and scales it as temperatures in the CPU rise.

Nothing quite compares to listening to the actual noise created by a heatsink in operation. To do that, click on the little headphones icon below and play the sample MP3 files for the heatsink running with its fan at full speed.

frostytech acoustic sampling chamber - full speed
	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 2600 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	CNPS7700-Cu	low	35.1 dB	Intel/AMD
Thermalfly	F1-IACSHA	low	35.4 dB	Intel/AMD
Intel	Stock Pentium D	low	40.5 dB	Intel
Coolermaster	Hyper48		43.6 dB	Intel/AMD
Zalman	CNPS7000B-CU	high	44.9 dB	Intel/AMD
Scythe	Shogun	high	45.9 dB	Intel/AMD
Intel	Stock Pentium D	high	47.5 dB	Intel
Spire	SP601B3		48.9 dB	Intel/AMD
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
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
Thermalright	Ultra 120		53.7 dB	Intel/AMD
Verax	Quattro 1	high	55.4 dB	Intel/AMD
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
Gigabyte	3D Cooler-Pro	high	62.5 dB	Intel/AMD
Gigabyte	3D Cooler-Ultra	high	63.0 dB	Intel/AMD
Gigabyte	GH-PCU23-VE	high	65.6 dB	Intel/AMD
ASUS	Starice	high	67.4 dB	Intel/AMD
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 92mm fan spinning at the full 2650RPM, the Zalman CNPS9500 AT heatsink produces about 53.5 dBA noise. When it is connected to a PWM compatible motherboard, noise levels are reduced to as low as ~35 dBA. Frostytech was unable to produce results consistent with a fan speed of 1300RPM by reducing fan voltage (standard 3-pin fan speed controller), so the low speed fan measurements have been omitted from the official results. By way of comparison, other CNPS9500-class heatsinks generally make as little as 36 dBA when running at 1300RPM. Our attempts to adjust the PWM fan speed down resulted in noise levels of 27.5 dBA - indicating fan speed below minimum design criteria.

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 Zalman CNPS9500 AT heatsink has a surface roughness of approximately 12 microinches, which is considered very good. Next, let's see how this heatsink handles the heat compared to a selection of other heatsinks!