The Zerotherm Zen FZ120 is a conventional, high performance, tower heatsink for CPUs — it has four U-shaped heatpipes, tightly packed fins, and a 120mm PWM fan attached via wire clips. It sports a few curves and contours reminiscent of the BTF80/BTF90 “butterfly” coolers (which were quite good)… but the sheer size of the new Zen makes it a more serious contender.
June 22, 2008 by Lawrence Lee
|ZEROtherm Zen FZ120|
LGA775 & K8 CPU Cooler
Zerotherm is branded in our minds as the ones responsible for the BTF80
and BTF90 CPU coolers… it’s hard to forget heatsinks shaped
like Butterflies. Fortunately, they turned out to be good performers, and we hope their newest product follows suit. The
Zen FZ120 is a more or less conventional tower heatsink — it has four heatpipes, tightly packed fins, and a 120mm PWM fan attached
via wire clips. However, it does sport a few curves and contours reminiscent of
More often than we like, heatsinks ship with large, unwieldy boxes and
a dreaded plastic blisterpack inside. The Zen however ships in a relatively eco-friendly
compact box without extraneous packaging. It also lacks gaudy artwork on the
outside, presenting itself with very little fanfare. Inside you will find the
heatsink itself, a transparent 120mm fan, a common AMD mounting clip, a LGA775
mounting frame and backplate, fan clips, fan isolation rubber strips, a tube of thermal
grease and instruction guide.
Zerotherm Zen FZ120: Key Features
(from the product
| Feature & Brief||Our Comment|
| Best Performance among|
120mm air cooling CPU coolers
|To be determined…|
| Effective 8-line Heat pipe|
| The Zen’s four U-shaped heatpipes|
act as eight.
| Honeycomb structure for|
optimized air flow.
| The fins at the center of the Zen|
are out of alignment with the rest of the heatsink, creating an overlapping
|120mm fan for max. air-flow||Standard for modern heatsinks.|
(Automatic Fan Control)
| A welcome addition. More fans should|
have the PWM feature.
| Silence Innovations|
Min. 19 .5 dBA at 1,100 rpm
Max. 31.4 dBA at 1,800 rpm
| As always, specified noise levels|
must be taken with a grain of salt.
|Support latest Intel & AMD CPUs||As it should.|
Zerotherm Zen FZ120: Specifications
(from the product
|Dimensions|| 126 X 61 X 156 mm|
(4.96 X 2.40 X 6.14 inch)
|Weight||670g (Without Clip Components)|
|Matreials||Fin – Aluminum|
|Base – Copper|
|Heat Pipe – Copper|
|Heat Dissipation Area||6,827 cm² (1,058 inch²)|
|Cooling Capacity||Over 150W|
|Fan Size||120 X 25 mm (4.72 X 0.98 inch)|
|Fans Speed||1,100 ~ 1,800 rpm (± 10%)|
|Acoustic Noise||Min. 19.5 ~ Max. 31.4 dBA (± 10%)|
|Connector||4 Pin, PWM|
|Operating Voltage||5.0 ~ 13.8 VDC|
|Airflow Rate||59.48 CFM|
Zerotherm Zen FZ120: Compatibility
(from the product
|Intel||CoreTM2 Extreme|| Socket-T|
| Support All|
|AMD||Phenom X3 / X4|| Socket|
939 / 940 / AM2
| Support All|
|Athlon64 FX X2 / BE|
|Intel||Socket 478, 771, 603, 604|
|AMD|| Socket 754, Socket F or|
The Zen bears a resemblence to the Thermalright
Ultra-120. The size and overall shape is very similar.
Unlike the Ultra-120, the Zen’s heatpipes are positioned in a straight line
rather than staggered, and lack the nickel coating.
The Zen’s design also has many many twists and turns, both in its interior
and on its exterior. The surface of the heatsink that contacts the fan is contoured,
as are the sides, creating a generally wavy appearance. The way the fins are
shaped create a unique overlapping "honeycomb" pattern in the center.
The fins on the outside curve upward at the center, but in the middle they curve
While the interior curvature increases the amount of surface area subject to
direct airflow, it also makes impedance more of a factor, at least at the center.
The fin spacing is already fairly tight at approximately 1.8mm.
From the side it’s evident that the Zen is quite narrow, and its fins thin. We measured them to be approximately 0.37 mm thick.
THE BASE & INSTALLATION
The base and mounting system is vital to the performance of
any heatsink. Without proper contact, the heatsink design is meaningless.
The base and heatpipes are both comprised of copper, and they are clearly joined with solder. This is the only place on the heatsink where solder is visible; the fins, in contrast, appear to be just tightly press-fitted. A mounting plate (made of cast steel or aluminum) sits on top of the base, holding everything in place. No
The surface of the base was very flat and had a pleasant
gleam. Some very faint circular machine marks were visible.
The LGA775 frame is attached via four screws to the mounting
plate. Four spring-loaded screws secure it to a backplate placed on the back
of the mainboard. This does require access to both sides of the motherboard, which means installation on an existing system calls for the motherboard to be removed. It’s more work, but through-the-board bolt mounting is the most secure for any heatsink, especially heavy, tall ones like this Zen.
The Zen installed very easily. An ordinary screwdriver was used to tighten the screws; the fins do not overhang the screws because of their relatively narrow depth. You simply tighten each screw as far as it will go, and the captive spring takes care of the tension. The fit was quite snug, as it should be. The fan is attached via two metal wire clips which are inserted
into holes located on the top and bottom fin on each side. The fan can be
decoupled slightly by strips of rubbery isolation material included in the package.
Measurements of some basic physical attributes have been
added to our test routine.
Zerotherm Zen FZ120s: SPCR Measurements
|Weight|| 610 g (heatsink|
640 g (heatsink and mounting frame/screws)
760 g (heatsink, mounting frame/screws, stock fan and accessories)
|Fin thickness||~0.37 mm|
|Fin spacing||~1.80 mm|
|Vertical Clearance (northbridge)|| ~43 mm (measured from the|
PCB to the furthest reach of the heatsink)
|Overhang (PSU)|| ~12 mm (this|
will depend on the distance from the CPU socket to the edge of the PCB)
A comparison of fin thickness and spacing among various tower
heatsinks is interesting. The Zen’s fins are quite thin and spaced tightly.
Comparison: Fin Thickness & Spacing
Thermalright HR-01 Plus
Zerotherm Zen FZ120
Testing was done according to our
unique heatsink testing methodology, and the reference fan was profiled
using our standard fan testing
methodology. A quick summary of the components, tools, and procedures
Key Components in Heatsink Test Platform:
Nexus 120 fan measurements
Noise measurements were made with the fan powered from the lab’s variable DC
power supply while the rest of the system was off to ensure that system noise
did not skew the measurements.
Load testing was accomplished using CPUBurn to stress
the processor, and the graph function in SpeedFan was used to make sure that
the load temperature was stable for at least ten minutes. The stock fan was
tested at various voltages to represent a good cross-section of its airflow
and noise performance.
The ambient conditions during testing were 15 dBA and 21°C.
Stock Fan Testing
The included stock fan is a clear plastic 120mm fan with a 4-pin PWM connector.
The blade design is similar to Panaflo and Yate Loon fans — the trailing edges
are more or less straight, and pass by the struts at an angle (which is better for reduced tonal noise).
|Model Number||SFA1225MU-12P||Airflow Rating||59.48 CFM|
|Bearing Type||Sleeve||RPM Rating||1,100 ~ 1,800 rpm (± 10%)|
|Hub Size||1.58"||Noise Rating||Min. 19.5 ~ Max. 31.4 dBA (± 10%)|
|Frame Size||120 x 120 x 25 mm||Header Type||4-pin PWM|
800Hz tonal peak
Fan @ 12V: Very buzzy with lots of chatter, mainly due to vibration.
The chatter lessens if held firmly in free air or properly secured on a heatsink
as opposed to standing unsupported on a hard or soft surface. At 36 dBA, it
is loud and annoying.
Fan @ 9V: Much smoother, with only a slight whine detectable.
The SPL registered at 25 dBA with a tonal peak at 800Hz.
Fan @ 8V: The noise level was reduced to a gentle hum. It’s quiet and unobtrusive.
Fan @ 7V: The fan is effectively silent. It sounded very
smooth with some clicking evident at close range.
Overall, it behaves more or less typically for a sleeve bearing PWM fan. Its
acoustics are lousy at full speed, but when undervolted, it quiets down nicely.
Zereotherm Zen FZ120 w/ stock fan
Zereotherm Zen FZ120 w/ reference Nexus fan
| Load Temp: CPUBurn for ~10 mins.|
°C Rise: Temperature rise above ambient (21°C) at load.
°C/W: based on the amount of heat dissipated by the CPU (measured
78W); lower is better.
Zen performed extremely well with the stock fan, especially at higher speeds
— the rise above ambient was only 12°C and 15°C with the fan at 12V and
9V respectively. Performance dropped off significantly when the fan voltage
was lowered most likely due to tight fin spacing.
Switching to our reference Nexus fan dramatically improved the performance-to-noise
ratio. It managed to deliver approximately the same level of cooling at each voltage setting, but with
much less noise. For example, when both fans were set to 7V, the Nexus fan registered
1 dBA lower, yet still managed to deliver a 6°C improvement in CPU temperature.
Comparison: Zen vs. Top Heatsinks w/ Reference Nexus Fan
Against the competition, the Zerotherm Zen performed well enough to take
the number four spot, slightly edging out the Scythe
Ninja Copper. While it is only about two degrees off our new favorite,
the Thermalright HR-01 Plus,
its tight fin spacing becomes an issue when the airflow is lowered to extreme
levels. Like the Xigmatek
HDT-S1283 and Ultra-120
eXtreme, the Zen takes a sizable performance hit when the Nexus fan
is slowed from 7V to 5V.
MP3 SOUND RECORDINGS
The recording begins with a six second stretch of the ambient noise of the test
room. This is followed by 10 seconds at each voltage level. Please set your playback volume so that the ambient noise is almost inaudible,
then don’t adjust the volume control again. For best results, save the sound
file to your own PC, then listen.
Zerotherm Zen FZ120 with stock
fan at 7V, 8V, 9V and 12V at 1m (Watch out for the 12V level; it’s noisy!)
"Real Silent 120mm fan" (at 5V, 7V, 9V and 12V at 1m)
The Zerotherm Zen FZ120 is a formidable CPU cooler. Not only does it perform
well, its mounting system is secure, and the installation procedure is straightforward.
There is no need to fiddle around with various sets of screws, wings, nuts,
washers or other doo-dads — manual dexterity is taken out of the equation.
It’s also an all-in-one solution, as a fan with PWM functionality is included.
The fan is a weak point. It is a fairly
typical stock fan — loud at full speed, with mediocre acoustic quality.
Fortunately, lowering the fan speed should be easy since almost all current motherboards sport PWM fan speed control. When slowed
to 700 RPM or lower, it is quiet enough for most users. While it doesn’t perform as well as
our reference Nexus fan, that is not unusual. Fan selection is usually an afterthought
for most manufacturers, and they tend to choose high airflow capability over best acoustics.
Overall, the Zen is an excellent heatsink with few surprises. Its US$50 price tag is pretty good unless you’re not satisfied with the stock fan. But at least one of SPCR’s affiliate online stores is selling it for as low as $40, which is an excellent deal.
Zerotherm Zen FZ120
* Great performance
* Included fan too loud at full speed
Our thanks to ZEROtherm
for the Zen heatsink sample.
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