Sibak AC01

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SUMMARY: Interesting design, OK peformance.


Dimensions: 83 x 69 x 40mm; Fan: 60mm, 23 cfm @ 4900 rpm; Weight: 360 gm.

SIBAK is a new company on the cooling scene and one of their entries, the Sibak AC-01-625B, is one of their more interesting designs. It’s a radial fin design with a copper core.

The base


is fairly smooth – I could not feel any machining marks. There vents allow some air to cool the CPU carrier, but it’s minimal.

The back


has a rather incongruous inscription. What’s more interesting is what’s inside:

Sibak Inside

The copper core runs top to bottom, contacting the fins at each end. The problem I see with this is the limited contact area between the copper core and the aluminum fins – more surface area contact would most likely increase heat transfer. In addition, as with so many copper-aluminum matings, the quality of the bond between the two is critical to performance.

The clip requires a screwdriver to mount/dismount on the socket. Although a pain, it’s very secure. Interesting to note that the rear clip engages all three lugs while the front only one.

The fan is not particularly noisy – I measured noise levels 8″ from the fan’s intake with a Radio Shack sound meter at 61 dBA – slightly less than a YS Tech 26 cfm (manufacturers measure fan noise something like 3 feet away).


The Sibak was first tested on the CPU Die Simulator which gives results that are unaffected by motherboard influences. The Sibak was then run on a Shuttle AK31 – MBM is the in-socket diode reading.


Die Temp

Ambient Temp



Simulator, 77.6 Watts

59.6 C

18.8 C



TEST RESULTS – Motherboards

CPU Die Temp

Ambient Temp




XP @ 1466/Shuttle AK31 (65 watts)

46.9 C

19.2 C



38 C

Delta = CPU temp – Ambient Temp
C/W = Delta / CPU Watts

Interpreting C/W: For every watt the CPU radiates, the heatsink will cool the core by the (C/W x watts) plus ambient temp. For example, at an ambient temp of 25 C, a C/W of 0.25 with a CPU radiating 50 watts means that the CPU core temp will be 50 x 0.25 = 12.5 C over ambient temp, or 37.5 C. The lower the C/W, the better.

Die Simulator results place the Sibak in the lower ranks of heatsinks (Heatsink Ranking). Note the 9C difference between the XP diode reading and the in-socket diode.


The Sibak AC-01-625B is nice to look at and an interesting design, but falls short of top rank performance. An OK heatsink for non-critical applications.

Thanks again to SIBAK for sending this sample our way. Sibak is looking for distribution – contact details:

SIBAK COOLER (explotech co., ltd)
5F, No. 114 Tein Mu East Raod
Taipei, Taiwan, ROC
886-2-28772086, fax 886-2-28771142
Email Sibak
Some background on SIBAK from Computex.

Email Joe


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