Information not expressly stated in the Final Rise above Ambient Temperature Test Results List concerns the pre-applied thermal pad (we remove this for testing any way), the number of fans on each heatsink, general fan noise and clip force observations, and ambient temperature measurements. As always, FrostyTech's Synthetic Temperature Test results for the Socket 478 Intel Pentium 4 platform are grouped according to the results for the 100W test die.

FrostyTech Synthetic Temperature Heatsink Test Results: *Ranked according to 100W interface die test results.

( Socket 478 - Pentium4 ) Rise Above Ambient Temp. (C)
Mfg.	Model	27mm large copper block		27mm large copper block
		50W		100W
Gigabyte (high)	PCU31-VH	12.5		22.3
Coolermaster (high)	Hyper6 KHCV81U1	12.4		23.4
Asus (high)	Crux P4 XB7N	13.9		24.4
Zalman	CNPS7000A-Cu	12.4		24.9
Alpha	S-PAL8952	12.7		25.4
AVC	Z7U7408001	12.9		25.8
Alpha	PAL8942	14.7		26.1
Zalman	CNPS7000-Cu	14.1		27.7
AVC	117140	15.2		27.8
JMC Products	401100	15.6		27.9
Coolermaster (high)	Jet4	12.6		28.1
Taisol	CEP447181	14.6		28.7
Jetart	JAP416A	11.8		29.1
Thermal Integration	TI-A8736N	12.4		29.1
Arkua	8568	15.4		29.3
Intel	Stock 3.06GHz	15.0		30.1
Vantec	VP4-7245	18.0		31.7
Verax	Polargate AL S	17.0		32.9
AOpen	ACP4SH	17.4		33.0
Scythe (6" dist.)	NCU-2000	17.2		33.4
Scythe	Kamakaze	18.9		34.1
Spire	SP420B8	17.4		36.2
Evercool	NW9F715CA	19.1		38.5
Aopen	ACP4LC	17.9		38.8
Arctic Cooling	SuperSilent4 Pro	21.7		43.0
Verax	P16Cu	22.0		45.1
Verax (high)	P17CuX	27.8		47.6
Cooljag	2QC/180	29.3		60.1
Cooljag	JACE2DC/180	30.7		61.6
Cooljag	E44C/180	33.8		66.9
Dynatron	DC1U-B02	32.9		67.4
		50W		100W

What the Aopen ACP4SH makes up for in noise translates into pretty good thermal performance. In this reference list of heatsinks, the ACP4SH ranks in with a very respectable 33 degrees Celsius rise above ambient temperature on the 100W synthetic temperature test platform. This is just a few degrees off from the stock 3.06GHz Intel heatsink, and that makes the Aopen ACP4SH a good all around option.

The heatsink is really best suited to SFF PC use where there exists fan speed control relative to CPU temperature. Were the ACP4SH to be run at full tilt continuously, the noise levels would not be desirable. With the heatsink fan speed scaling to meet the thermal demand it offers a much more advantages cooling solution to the user. Bottom line, the Aopen ACP4SH is a compact socket 478 cooler that can handle average amounts of heat, and is well suited to everyday desktop cooling so long as the system is able to manage fan RPM itself.

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1. Scythe NCU-2000 Pentium4 Heatsink Review
2. Gigabyte 3DCooler-Ultra PCU31-VH P4/K7/K8 Heatsink Review
3. Coolermaster Jet 4 ICB-V83 Pentium 4 Heatsink
4. Cooljag E44C/180 Pentium 4 1U Heatsink Review
5. Cooljag 2QC/180 1U Socket 478 Heatsink Review
6. Cooljag JACE2DC/180 1U Socket 478 Heatsink Review
7. Alpha Novatech S-PAL8952 Pentium4 Heatsink Review
8. Verax P17CuX Ultra Quiet Heatsink Review