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
Apack	Zerotherm BTF90		21.8	12.7	52.1
Apack	Zerotherm BTF80		22.8	13.9	51.9
Thermalfly	F1-IACSHA	high	29.0	18.3	60.4
Zalman	CNPS9500 AT		29.6	17.3	53.3
Alpha Novatech	PRE9060M92P	high	29.9	18.5	51.5
Akasa	AK-961		30.0	18.7	60.7
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
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
Intel	Stock Pentium D	low	40.3	23.9	40.5
Cooljag	OAK-H2	low	94.5	51.7	29.2
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.

the heat output from intel processors varies widely between single and multi-core processors, so we've settled on two values which represent the upper limit of both existing CPU families. With a 150W heat load applied by the Intel LGA775 version of FrostyTech's synthetic thermal test platform, the Cooljag OAK-H heatsink yields a rise above ambient temperature of 38.5°C, with 55.7dBA noise. That is a satisfactory result, and virtually identical to the OAK-H2 model in fact. It is not particularly impressive considering the fan is running at its full speed however. At the much quieter fan speed of ~600-1800RPM (fan receiving 6V), temperatures rise dramatically to 95.3°C (29.5 dBA) over ambient with the same heat load. Though running whisper quiet, Cooljag OAK-H heatsink absolutely fails as a low noise cooler just as the OAK-H2 model did.

The Cooljag OAK-H heatsink was also tested with an 85W heat load. With the fan running at 3500RPM the heatsink maintained a very respectable temperature of 22.9°C over ambient. But yet again, when the fan speed was reduced for the second portion of the 85W test, the temperature rose substantially to 54.5°C.

Clearly, the Cooljag OAK-H heatsink is not well equipped to handle heat loads much more than 85W if the fan is not spinning at its fastest speed. With a 150W heat load applied, the heatsink fairs satisfactorily so long as fan speed is maintained at the full 3500RPM rate. The big problem with this is that the Cooljag OAK-H heatsink defaults to its low fan speed when connected to a legacy 3-pin motherboard fan header automatically. Hence, this heatsink is not recommendable for non-PWM motherboards. We would also advise maintaining things at full fan speed if you must use this heatsink, or save yourself $40 and stick with the original stock Intel socket 775 heatsink.

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