Acoustic Samples: Listen to this Heatsink!

There was an odd aspect of the fan that we noticed while testing the Cho Liang heatsink. The RPM, or noise signature would constantly fluctuate in such a way that one of two things were happening. The first may have been that the bearings were causing the fan to stick, or rotate less freely on uneven intervals but I find that unlikely. The second, and more plausible explanation was that the fan was experiences variable amounts of back pressure.

All cooling systems experience a level of back pressure, but with this Cho Liang heatsink it seemed as though air would move through fins freely for a few seconds and then begin to back up and overflow, with the entire scenario repeating itself over an over. It was interesting, and in the long run the fluctuations in noise signature could become annoying if they superceded the sound of the powersupply and other case fans for example.

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

Sound Level Measurements:

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 Decibel readings with a sound level meter. These results may be higher than the manufacturer's listed specs, but then again these are real world measurements.

FrostyTech Sound Level Results
-	Manufacturer	Model	Noise Level	Scale
	Coolermaster	HHC-L61	42.2 dB	quiet
	Coolermaster	HSC-V62	43.7 dB
	Spire	5F263	44.5 dB
	JMC Prducts	400023	46.6 dB
	Zalman	All Flower HSF	47.4/28.9 dB
	Taisol	CGK760092	48.4 dB
	GlacialTech	Igloo 2310	49.4 dB
	Cho-Liang	CB0307U-17	49.5 dB
	Arkua	628	50.7 dB
	Cho Liang	CB0315U17	52.5 dB
	Noisecontrol	Silverado	50.8 dB
	NengTyi	XPC5000	52.4 dB
	Titan	TTC-CU5TB	57.6 dB
	Ajigo	MF014-021	52.8 dB
	Ajigo	SF017-011	53.6 dB
	Spire	5T235	52.5 dB
	Thermal Integration	TI-V77L	53.0 dB
	Tocools	Crown	54.5 dB
	Cybercooler	P5750	55.4 dB
	Sibak	AT01515B	55.8 dB
	Sibak	AE01625B	58.2 dB
	Sibak	AC02625B	59.7 dB
	Coolermaster	HHC-001	59.9 dB
	Dynatron	DY1206BH-625	63.3 dB
	Dynatron	DC1206BMP	65.1 dB	louder

Below 55 dB is usually pretty good, and this copper Cho Liang heatsink manages to come in at 52.5 dB which pretty great. There are way too many heatsinks on the market today which are just too noisy, so it can sometimes be a good idea to buy a heatsink with a smaller, lower noise fan first. If temperatures dictate, a switch to larger, higher RPM fan can always occur at a later date as needed.