FrostyTech Mk.II Synthetic Thermal Heatsink Test Results Intel Pentium D / Extreme Edition & Quad Core class heatsinks tested at 150W Intel Core 2 Duo / Pentium 4 / Celeron class heatsinks tested at 85W Results based on readings from a 30x30mm copper interface die with 150W and 85W heat loads applied on the LGA775 version of the Mk.II Test Platform. Temperature results listed for each heatsink were calculated by determining the rise over ambient temperatures at time of test. Information on Frostytech's test methodology is available here. Socket 775 compatible CPU heatsinks
Manufacturer:	Model No.:	Fan Speed:	150W Thermal Test* (°C)	85W Thermal Test (°C)	Noise Level (dBA)
Thermalright	Ultra 120		17.8	10.6	53.7
Zalman	CNPS9700 LED	high	19.0	10.4	56.5
Thermalright	Ultra-90	high	19.6	13.0	56.2
Enzotech	Ultra-X	high	20.0	8.5	59.1
Apack	Zerotherm BTF90		21.8	12.7	52.1
Apack	Zerotherm BTF80		22.8	13.9	51.9
Cooljag	Falcon 92-AL	high	23.2	14.2	52.1
Rosewill	RCX-Z3	high	23.3	14.0	58.6
Scythe	Mine Rev. B		23.6	15.0	36.8
Cooljag	Falcon 92-Cu	high	23.6	14.8	52.8
Akasa	AK-920	high	24.3	14.1	52.9
Asus	Arctic Square	high	24.9	14.9	44.9
Akasa	AK-922 (EVObue)	high	25.5	15.4	60.3
Thermalfly	F1-IACSHA	high	29.0	18.3	60.4
Thermalfly	I75DUB	high	29.5	16.8	68.5
Zalman	CNPS9500 AT		29.6	17.3	53.3
Alpha Novatech	PRE9060M92P	high	29.9	18.5	51.5
Scythe	Kama Cross		30.0	18.8	40.0
Akasa	AK-961		30.0	18.7	60.7
Rosewill	RCX-Z2-EX	high	30.1	18.7	45.9
nPowertek	NPH-775-1		30.1	18.8	50.1
Sunon	Waturbo		30.6	18.3	57.5
Apack	CF800	high	31.4	20.7	48.4
Thermaltake	Jungle512	high	31.6	20.4	60.8
Xigmatek	AIO-S80DP	high	32.4	21.4	55.0
Scythe	Katana II		32.5	18.6	37.9
Rosewill	RCX-Z2		32.6	19.3	59.9
Zalman	CNPS7700-Cu	high	32.9	19.7	50.7
Apack	CF900	high	32.9	20.3	48.3
Evercool	PT02-9232CP		33.3	19.9	63.3
Zalman	CNPS7700-Cu LED	high	33.5	20.6	49.8
Intel	Stock Pentium D	high	33.8	20.7	47.5
nPowerTek	SF775-2	high	34.7	21.1	64.6
Akasa	AK-960E		36.1	21.4	56.3
Thermalfly	I75DUH		37.8	22.8	48.7
Cooljag	OAK-H	high	38.5	22.9	55.7
Cooljag	OAK-H2	high	38.6	24.1	55.6
LS Cable	SHS-T700		38.7	22.8	48.5
Rosewill	RCX-Z3	low	42.4	25.4	45.6
Cooljag	OAK-H	low	95.3	54.5	29.5
			150W Thermal Test (°C)	85W Thermal Test (°C)	Noise Level (dBA)
*Heatsinks are ranked according to the 150W thermal test results column (rise over ambient temp.). Low temperatures with low noise levels are considered best. For reference heatsinks with variable-speed fans, only the high speed (12V) fan test result is included in the comparison sheet; more detailed results reside in each specific heatsink review.

Intel processors vary widely in heat output between single and multi-core processors, so Frostytech relies upon on two different thermal values to represent the upper limits of existing Intel single and multi-core CPU families. First off, a 150W heat load was applied by the Intel LGA775 version of FrostyTech's synthetic thermal test platform to the Rosewill RCX-Z3 heatsink. This yielded a rise above ambient temperature of 23.3°C, with 58.6dBA noise. That's a good result, but not low enough to be considered top of the line... and nearly 60 dBA is somewhat loud.

When the 92mm PWM fan speed was dropped down to about 1200RPM, temperatures rose to 42.4°C over ambient, while noise levels fell down to a much more reasonable 45.6 dBA. When faced with a 150W heat load, Rosewill's RCX-Z3 heatsink handles it well, so long as air flow is sufficient.

The Rosewill RCX-Z3 heatsink was next tested with an 85W heat load. In this case the heatsink maintained a good 14.0°C temperature over ambient at full fan speed. As fan speed was reduced to low noise mode, the heatsink reacted in a predictable manner - the synthetic CPU die temperatures rose to 25.4°C.

Clearly as we can see from the synthetic thermal test results here, the Rosewill RCX-Z3 heatsink is only really able to shine when its fan is loudly spinning away at full RPM. As the volume of airflow passing through its many aluminum fins decreases, the heatsink quickly looses effectiveness and the plastic fan shroud starts trapping the heat in. In the end, we're left wondering if it would be better ditching the blue LEDs and plastic fan shroud entirely so the heatsink could potentially be operated with a quieter fan. As it stands, the Rosewill RCX-Z3 is only worthwhile when going at full tilt, and then it is just too loud for modern day computer users to accept.

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