SUMMARY: High noise, low performance.


Size: 68 x 110 x 70mm; Weight: 151 grams.

The good guys at Cibna were nice enough to send the newest version of the ZEROtherm for a test spin. This is a heatpipe heatsink featuring three pipes running up to a finned radiator:


The ZEROtherm ships with a Sym Bang fan, #D7025V12SHB – a 70 x 25mm unit rated at 50 cfm @ 6000 rpm, 53.5 dBA¹. I found it to be on the noisy side – I measured its noise at 67 dBA with a Radio Shack sound meter 8″ from the fan’s intake, close to a Delta 38 (about 69 dBA).

The base shows polishing marks:


When I ran my nail over it, I could feel the ridges – not the smoothest finish I’ve seen. The mounting clip is quite secure but does require a screwdriver to mount the Socket A version.


The ZEROtherm was tested on the CPU Die Simulator which gives results that are unaffected by motherboard influences.


Die Temp
Ambient Temp
ZEROtherm, 6006 rpm
59.0 C
22.2 C
36.8 C

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

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.

Die Simulator results place the ZEROtherm in the lower rank of Socket A heatsinks tested to date (Heatsink Ranking). It has not substantially changed from the first version tested.


The ZEROtherm is not a particularly aggressive choice for Socket A or P4 cooling. It’s noisy, with its 6000 rpm fan, and performance is subdued.

Thanks again to Cibna for sending this our way.

¹Note that manufacturers measure fan noise usually 3 feet from the fan.

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