Asetek VapoChill Micro ™ Extreme

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Heatsink Test – Joe

SUMMARY: A top-notch heatsink which can handle high wattage CPUs, is very easy to mount, not heavy and looks great.

VapoChill Micro

Size: 139 × 98 × 50 mm; Weight: 278 grams (355 grams with 92 mm fan)

The good guys at Asetek were nice enough to send their newest product, the VapoChill Micro Extreme for a test spin. This is a thermosyphon which uses the refrigerant gas R134a for the phase change. The VapoChill Micro is rated to handle 150 watts and is designed to fit P4, Socket LGA 775 and K8 motherboards.

Looking at the Micro from the front

VapoChill Micro Front

shows the plastic fan mount – it is thin and feels a bit on the flimsy side, but once the fan is mounted on it, it firms up. The fan mount is angled such that it directs air onto the motherboard. High-End & Extreme fans are PWM (Pulse With Modulation) compatible for motherboards which support this capability.

Note the three pipes coming out of a plenum attached to the base. The following diagram


Diagram courtesy of Asetek

shows how the VapoChill Micro works – the refirigerant is a liquid at the base – heat turns it into a gas, which is then cooled by the radiator. This condenses the gas back into a liquid, which flows down the pipes back to the base to start the cycle over. There are no moving parts to wear out; the only caveat is that it must be mounted such that the radiator is above the base, either horizontally or vertically.

The VapoChill Micro Extreme ships with a fan controller and parts for P4, Socket LGA 775 and K8 mounting:


The base is well finished:


The dots are pre-applied heatsink compound. When I ran my nail over the base, I could not feel or hear any ridges.


The VapoChill Micro Extreme was tested on an Acorp 4S845A motherboard with a modified P4 1500 to read CPU case temps.

I varied fan speed (rated 3800 rpm, 74 cfm) using Asetek’s fan controller to get a performance range, measuring rpms using an Omega digital tachometer. I measured fan noise with a Radio Shack sound meter 8″ from the fan’s intake. These are not comparable to noise levels reported by fan manufacturers; noise is usually measured at three feet from the fan.


Case Temp
Ambient Temp
Die Temp¹
VapoChill Micro, 3640 rpm, 63 dBA
34.5 C
26.0 C
VapoChill Micro, 2588 rpm, 52 dBA
35.9 C
25.1 C
VapoChill Micro, 1426 rpm, <50 dBA
38.1 C
24.7 C
VapoChill Micro, 897 rpm, <50 dBA
44.2 C
24.6 C

¹Die Temp as measured by the P4 on-die diode, per MBM.

Interpreting C/W: For every watt (CPUw) that the CPU
consumes, the HSF will limit the CPU’s temperature rise to (C/W x CPUw)
plus the temperature at the HSF’s fan inlet. For example, at an ambient temp of 25 C, a C/W of 0.25 with a CPU radiating 50 watts means that CPU temp will increase 50 x 0.25 = 12.5 C over ambient temp, or 37.5 C. The lower the C/W, the better.

Results place the VapoChill Micro in the topmost rank of P4 heatsinks tested to date (Heatsink Ranking).

Of particular note is performance at reduced fan rpms – the difference under CPU stress up to about 1500 rpm is a moderate 7ºC at 100 watts – very good low noise performance; however, performance at fan speeds under 1500 rpm does degrade quickly, as the results at 897 rpm show.

I also tested the Micro on the CPU die tester, even though it’s not optimized for it. It tested at a C/W of 0.28, which would place it among the top rank of heatsinks tested.


Asetek has opened the gates on competitive thermosyphon CPU heatsinks with an excellent product. The VapoChill Micro ™ Extreme is a top-notch heatsink which can handle high wattage CPUs, is very easy to mount, not heavy and looks great. MSRP High-End $39.99, Extreme Performance $44.99, Ultra Low Noise $49.99.

Disclosure: Joe Citarella has a financial interest in a company developing thermosyphon products for electronic chip cooling (not Asetek).

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