The Quietude II betrays its name with a fair degree of noise from the fan. If you are looking to build a quiet computer you may want to avoid this particular heatsink, though it does perform well. The thermally controlled fan starts off moderately quiet, but as soon as the temperatures begin to rise it hits the high notes. To listen to this heatsink for yourself in operation, be sure to click on the little headphones icon below and download the Acoustic Sample MP3 file.

(high) 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. Measurements are made on the dB (A) scale.

FrostyTech Sound Level Results
-	Manufacturer	Model	Noise Level	Scale
	Zalman	CNPS7000-Cu	41.7 dB	Quiet
	Zalman	CNPS6500-AlCu	47.4/28.9 dB
	Intel	Socket 478	42.5 dB
	CoolJag	JVC661A	43.9 dB
	JMC	400124	47.2 dB
	Evercool	NW9F715CA	47.3 dB
	Arkua	848X-6B	49.3 dB
	Taisol	CEP426151A	50.7 dB
	JMC	400094	50.8 dB
	Vantec	CCK-7025	51.4 dB
	Arkua	838T-7G	51.7 dB
	JMC	401100	53.0 dB
	Dynatron	DC1207BMW	53.0 dB
	Spire	SP411C5	53.2 dB
	Dynatron	DC1207BMY	53.2 dB
	Dynatron	DC1207BMX	53.4 dB
	Thermal Integration (high)	TI-V7035TN	53.6 dB
	Zalman	CNPS5700D-Cu	53.8 dB
	Globalwin	VA476	54.2 dB
	Eumax	DW-45	54.2 dB
	Dynatron	DC1206BMV	55.1 dB
	Glacialtech	Igloo 3300	55.4 dB
	AVC	117140	56.1 dB
	Taisol	CCP445172	57.5 dB
	CPUMate	DIA10500	57.5 dB
	NengTyi	NW6700	58.0 dB
	Dynatron	DC1U-B02	62.2 dB
	Coolermaster	IHC-H71	64.4 dB
	Thermalright (high)	SLK-900U	67.2 dB	louder

The Spire Quietude II clocks in at 53.2 dBA which places it about middle in terms of the noise and the other reference coolers. This sound measurement was taken with the heatsink running at room temperature. Because the SP411C5 uses a thermally reactive fan, it does produce more noise when the heatsink is at elevated temperatures.