SIBAK AC-01-625B

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A quiet one for Mom — Joe

SUMMARY: Easy on the ears, too easy on performance – one for Mom.


Size: 73 x 72 x 59mm high; Fan: 70 x 15 mm, 26 cfm @ 4200 rpm; Weight: 260 gms

SIBAK was nice enough to send us their SIBAK AC-01-625B to test out. The picture on the site is dated as this model features a 70mm fan and sports a clip which engages all three socket lugs. I like this feature as it makes for extremely secure mounting – in addition, if you have a broken socket lug, a clip such as this is a necessity.

The heatsink is an all aluminum extrusion


of fairly conventional design. The base


is very nicely done – no machining marks discernible to the touch and flat.

The fan is an Everflow Model #R127015DU – a 70 x 15mm unit rated at 26 cfm @ 4200 rpm (note: The fan I had ran at about 4500 rpm; I took the specs from Sibak and this model might be slightly different). I found it to be tolerably quiet – I measured its noise at 62 dBA with a Radio Shack sound meter 8″ from the fan’s intake, substantially less than a Delta 38 (about 69 dBA). It’s also safe to use a motherboard fan header.

The fan is surrounded by a fairly attractive enclosure – but that’s all it is – the holes are strictly for looks.

The clip engages all three socket lugs – a bit of overkill for a heatsink this light, but I’ll take it. It does not require a screwdriver to mount and is easily mounted by hand – I wish more heatsinks came with such a clip.

In summary, a fairly conventional aluminum extrusion heatsink with a very secure and easy to use clip.


The Sibak was first tested on the CPU Die Simulator which gives results that are unaffected by motherboard influences. I then tested it on an Iwill KK266+ and Shuttle AK31, modified to read AMD’s on-die diode, as an example of what users might see on their systems.



Die Temp

Ambient Temp



Sibak AC-01-625B, 77.3w

56.6 C

19.9 C

36.7 C


TEST RESULTS – Motherboard

CPU Die Temp

Ambient Temp



CPU Back Temp

Palomino 1200, Iwill KK266+

39.3 C

21.7 C



41.2 C

XP @ 1467, Shuttle AK31

43.0 C

19.4 C



35 C¹

¹In-socket thermistor per MBM

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 AC-01-625B in the lower ranks of heatsinks (Heatsink Ranking).


Not a standout performer, but an OK cooler for Mom.

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 Road
Taipei, Taiwan, ROC
886-2-28772086, fax 886-2-28771142
Email Sibak
Some background on SIBAK from Computex.

Email Joe


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