Cooler Master Hyper N520 dual 92mm fan cooler

Table of Contents

Do two 92mm fans provide improvements on a tower heatsinks a smidgen smaller than the ones that use a 120mm diameter fan? This is one of the many questions we pose of a new CPU cooler from Cooler Master.

March 19, 2009 by Mike Chin

Hyper N520 CPU Cooler
Cooler Master
Street Price

Cooler Master is a major player in the retail CPU cooling and computer case markets. Naturally the company’s product roster is extensive and hard to keep track of. One of its newest CPU cooling products is the Hyper N520. Hyper is the name used for a few other cooling products; they appear to be part of a series, somewhat related in style. Most of them are tower designs where the fan blows across the motherboard instead of down.

Heatsinks remain one of the primary noise sources in a PC, as they are usually equipped with a fan, and most fans make audible noise. While CPUs generally run much cooler than they did a few years ago, some still push beyond 100W, and high speed, noisy fans are still basic tools used by heatsink designers. SPCR’s general recommendation for silent computing enthusiasts is to use a large heatsink with well spaced fins in conjunction with a large, quiet, slow speed fan which can move as much air as a smaller fan running at higher speed. The Hyper N520 varies a bit from this ideal in that it is equipped with two fans, and at 92mm diameter rather than 120mm, they are not as large as they could be, given the fairly large size of the heatsink. The proof, as always, is in the cooling.

The sample we received came without a retail package, but complete with two mounting systems and two fans. It has a serious appearance.

We bet the packaging is huge, colorful and full of plastics.


CoolerMaster Hyper N520: Key Features
(from the product
web page
Feature & Brief
Our Comment
Universal Design

* Intel (LGA 1366/LGA775)
* AMD (AM2+/AM2/940/939/754)

Optimum Air Flow

* Distinct appearance with dual fan bracket
* Unique dual fan cooling design ensures cool air accelerates straight through the heatsink

Each fan misses a bit of one bank of pipes.
Superior Cooling Performance

* Mirror finished copper base guarantees perfect contact between CPU and cooler
* 5 heat pipes optimize heat transfer



CoolerMaster Hyper N520: Specifications
(from the product
web page

The reference to 19 dBA noise level (more correctly, SPL or sound pressure level) without any other qualifications is disappointing. It raises more questions than it answers: Is that with one fan or both? At 1m distance? At 12V/full speed? In an anechoic chamber or a live room?


The size of the N520 puts it halfway in between a 120mm fan tower heatsink and a more conventional 92mm fan tower heatsink. It is pictured below with the Thermalright HR-01 Plus on the left and the Xigmatek HDT-964 on the right.

The N520’s width could accommodate a 120mm fan.


The fins are approximately 0.38 mm thick with 1.72 mm separation between them.
Fin spacing is fairly tight, compared to the 3mm of the Thermalright HR-01, and about the same as the Xigmatek HDT-964. Note the two short 3-pin fan cables connected in parallel with a Y-adapter.


The fans have a minimalist frame, with bits cut away from all over the frame. This is presumably to improve overall airflow and perhaps reduce turbulence noise. They are in a push-pull configuration: Both fans blow in the same direction. They are firmly bolted to a metal frame that wraps around the fins. They’re also offset a bit, by about 1.5cm. Neither gets as much airflow to one bank of heatpipes as the other, but with both fans, even airflow should be maintained.


The base is quite flat and smooth, though circular machining marks can be seen. The heatpipes are packed together tightly at the base. They appear to be soldered
to the base for better thermal conduction. Note that the three center heatpipes are U-shaped, as is the norm for tower heatsinks. The outer two are L-shaped. Hence the 5-heatpipe spec. It’s best to think of it as having 8 heatpipe lengths that feed heat up to the fins.


The cut slots on the sides of the frame are probably cosmetic.



The most critical aspect of installation is for the heatsink
to be securely mounted. The more firmly it is installed, the better the contact
between the heatsink’s base and the CPU itself. It’s also less likely to fall
off. Ease of installation is also important — a simple mounting scheme
means less time spent installing, and a reduced likelihood of screwing up.

The Hyper N520 employs bolt-through nuts with backplates for all the various CPU types it is compatible with. The assembly and mounting procedure is not too cumbersome, though our familarily with parts that were also used on the previously reviewed Hyper Z600 may have eased things for us. The end result should be a secure and tight fit, with a good bond between cooler base and CPU. Note that socket 1366 (Intel i7) hardware was not supplied; we presume this would be included in the retail box and be similar to the socket 775 hardware.

For AMD processors, the square shaped base allows the heatsink to be rotated within the mounting bracket, which means the fan airflow can be pointed to direction that is ideal for your setup. This is usually towards the back panel where there’s a case fan to exhaust the heat. Many tower heatsinks do not allow such fan direction rotation, which makes it more difficult for AMD users to tweak the cool and quiet performance of their rigs to the nth degree.

The mounting parts: AMD backplate and bracket on the top, Intel 775 backplate and bracket on the bottom. The small screws, nuts and washers on the right are shared.


These double-threaded screws are used for all the different mounting brackets. They screw into the bracket first, then are secured on the underside of the motherboard with nuts over the backplate.


Here’s one of the double-threaded screws with rubber grommet before installation.


Mounting arms with double-threaded screws attached to base, ready for installation. The best way to install is to place the heatsink so its base is facing up like above, then place the board with CPU already mounted over it, lining up the 4 screws to go into the 4 holes on the board. Just keep track of which way you want the fans to blow; usually, you want the air blowing toward the back of the case where there’s a case fan to exhaust the heat.


A nut driver head that can be used with a Philips head screw driver is supplied, but the raised flange on the backplate make it difficult to use.


On our socket 775 test platform, the heatsink remained within the boundaries of the motherboard.

Before thermal testing, we took some basic physical measurements.

Cooler Master Hyper N520: Physical Measurements
690 g (including fans and top mounting bracket)
Fin thickness
0.38 mm
Fin spacing
1.72 mm
Number of fins
Vertical Clearance
45 mm (measured from the
motherboard PCB to the heatsink’s bottom fin)
Horizontal Overhang
-5 mm (measured from the
edge of the heatsink to the top edge of our test motherboard’s PCB)


Comparison: Approximate Fin Thickness & Spacing
Fin Thickness
Fin Spacing
Scythe Ninja 2
0.39 mm
3.68 mm
Thermalright HR-01 Plus
0.45 mm
3.15 mm
Noctua NH-U12P
0.44 mm
2.63 mm
Noctua NH-C12P
0.47 mm
2.54 mm
Prolimatech Megahalems
0.50 mm
2.00 mm
Xigmatek HDT-S1283
0.33 mm
1.96 mm
Cooler Master Hyper N520
0.38 mm
Xigmatek HDT-S963
0.33 mm
1.72 mm
Thermalright Ultra-120
0.45 mm
1.42 mm

Testing was done according to our
unique heatsink testing methodology
, and the included fans were profiled
using our standard fan testing
. A quick summary of the components, tools, and procedures
follows below.

Key Components in Heatsink Test Platform

  • Intel
    Pentium D 950
    Presler core, C1 stepping. TDP of 95W; under our test load, it measures
    78W including losses in the VRMs.
  • Asus P5Q-EM motherboard. A microATX board with integrated graphics
    and short solid-state capacitors around the CPU socket, and a diminutive northbridge heatsink for maximum compatibility.
  • Intel X25-M
    80GB 2.5″ solid-state drive.
  • 1GB of Corsair XMS2 DDR2 memory. 2 x 512MB PC2-8500.
  • FSP Zen 300W
    fanless power supply.
  • Arctic Silver
    : Special fast-curing thermal interface material, designed
    specifically for test labs.

Measurement and Analysis Tools

  • Seasonic
    Power Angel
    for measuring AC power at the wall to ensure that the
    heat output remains consistent.
  • Custom-built, four-channel variable DC power supply, used to regulate
    the fan speed during the test.
  • PC-based spectrum analyzer:
    SpectraPlus with ACO Pacific mic and M-Audio digital
    audio interfaces.
  • Anechoic chamber
    with ambient level of 11 dBA or lower
  • Various other tools for testing fans, as documented in our
    standard fan testing methodology
  • SpeedFan, used to monitor the on-chip thermal sensor. This sensor is not
    calibrated, so results are not universally applicable.
  • CPUBurn
    , used to stress the CPU heavily, generating more heat than most
    real applications. Two instances are used to ensure that both cores are stressed.
  • Throttlewatch
    , used to monitor the throttling feature of the CPU to determine
    when overheating occurs.

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 Fans

The two fans are identical. Each is a somewhat unusual nine-blade 92mm
design. Translucent plastic is used; this is a material we’ve found in many fans that have strong tonal qualities. We suspect it adds tonal resonances to the overall noise signature. The basic geometry is not great, as the trailing edges of the blades are nearly parallel to the struts. For minimal tonal contribution, they should be as perpendicular as possible. (See Fan Blade Geometry on page 3 of the Anatomy of the Silent Fan for more details.) The other notable aspect of its design is that the frame has been cut away, perhaps to reduce mass and/or to minimize its turbulence effects.


Fan Specifications
Brand Cooler Master Power 0.31A (3.72W)
Model A9225-18CB-3BN-L1 or PLA09225S12M-3 Airflow 43.8 (total)
Bearing sleeve (likely) RPM 1800
Hub Size 1.54″ Noise 19 dBA
Frame Size 92 x 92 x 25 mm Header 3-pin
Weight 80 grams Start Voltage 3.2V
The data in the blue cells is provided by the manufacturer; we measured the data cited in the green cells


SPL – dBA@1m
1 fan
2 fans

Since there are two identical fans, they were tested individually to collect the data in the tables above. They were not identical, but close; the slightly faster of the two fans was cited for the single fan measurements. (The speed difference was about 30 RPM at 12V and less at the lower voltages.)

During all the audio testing, the fans were left on the heatsink, and the heatsink left mounted on the motherboard. The motherboard was placed on a table in the anechoic chamber. A standard letter paper pad was used under the motherboard to keep it from wobbling during audio testing.

In theory, two fans in push/pull configuration have the benefit of higher pressure than one, which makes it useful for a high impedance load between the two fans. However, the total airflow is limited to the free-air airflow capability of a single fan; they do not push double the air. So with a low impedance load, there is no advantage with using the dual-fan, push-pull configuration. The Hyper N520 isn’t 100% push-pull, however, because of the slight offset of the two fans, which represents perhaps 20% of the fan blades’ diameter. The other question is whether the impedance represented by the ~2″ distance through the 1.72mm gaps between 50 thin fins is a high enough impedance to make the push-pull setup worthwhile.

One fan was disconnected for the single fan measurements. There was no appreciable difference in the noise whether the “push” fan or the “pull” fan was disconnected. You could say, judging from the SPL measurements above, that there’s not much of a price to be paid for running two fans compared to just one. But subjectively, it was a different story.

Sound Impressions

Despite the S in the model name, which usually denotes sleeve bearing, this fan did not sound like a typical low-speed sleeve bearing fan. The buzzy quality was very similar to the sound of a bad ball-bearing fan. The two fans together sounded worse than one, despite the absence of change in the measured SPL.

@ 12V: While it could not be described as loud, the overall noise was highly tonal, with more than one or two main tones. There was both a buzzing as well as a clicking aspect to the sound, which made it basically unpleasant.

Furthermore, the two fans did not run at exactly the same speed, even though they were fed from the same source. This is not unusual, as one fan could have been a touch more efficient. The slight difference in speed (and primary frequencies) caused intermodulation to arise. This is sometimes referred to as a “beat” frequency, a third frequency of sound that arise from the interaction between two primary ones, and here it sounded like a kind of slow warble or a quick flutter, depending on the exact difference in speed (which varied as the voltage to the fans was changed – for example, the effect was not the same at 12V as at 9V).

If there is any variability in the voltage fed to the fans, the frequency of the intermodulation goes up and down, making it even more distracting and annoying. There was some variation in fan speed at 12V, and this drift might have been a function of the lab power supply or AC power variations. The effect was much more audible in the live (normal) test room where the cooling performance test was conducted than in the anechoic chamber, where there are no reflections to exacerbate the effect.

With just one fan, the overall noise improved, becoming a bit less tonal and the intermodulation effect disappeared, but the measured SPL did not change. The performance cost was 2°C, which is small. The change in overall noise might not be enough to accept, however. If you didn’t like the sound of the two fans at 12V, one fan at 12V might still sound too noisy to you.

@ 9V: Most of the turbulence noise faded, but the buzzing and clicking remained, at a much reduced level. The intermodulation sound was mostly gone. Inside a well-damped case, the overall sound level might be considered quiet. There seems little to be gained by running just one fan at this voltage and below; subjectively, the improvement is not great.

@ 7V: Again, the overall noise dropped further, the buzzy quality remained.

@ 5V: Very subdued in level, but up close, the buzzing and clicking character of the fan remained in evidence.

Cooling Results

Cooler Master Hyper N520: Cooling Performance
(data in brackets is with a single fan)
Fan Voltage
SPL dBA@1m
Temp °C
°C Rise
30 (30)
37 (39)
17 (19)
0.22 (0.24)
23 (22)
39 (42)
19 (22)
0.24 (0.28)
19 (18)
42 (47)
22 (27)
0.28 (0.35)
14 (14)
49 (55)
29 (35)
0.37 (0.45)
Load Temp: CPUBurn for ~10 mins.
°C Rise: Temperature rise above ambient (20°C) at load.
°C/W: based on the amount of heat dissipated by the CPU (78W); lower is better.

The Hyper N520 was a decent performer at the normal 12V, with a temperature rise of 17°C. It was too noisy for our taste, however, especially considering the unpleasant quality of the sound. With one fan, the subjective quality improved a bit, but probably not enough.

The performance at 9V dropped by only 2°C, while the noise dropped to 23 dBA. This is a much better balance.

At 7V, the performance dropped off by 5°C, which might be too much for an enthusiast system. A °C/W number above 0.25 is probably not acceptable for higher performance rigs that use 65W and higher TDP processors. The cooling performance at 5V is unacceptable.

With the N520, 9V is the highest drive voltage recommended for a quiet PC, and this is still well over 20 dBA. The 19°C rise over ambient is good enough for a processor as hot as ours in a cool room. In the confines of a case, in hotter weather, you might easily add 20°C to the CPU temperature, and while that’s still under the maximum recommended of 65~70°C, it’s probably as high as you’d want to go. Runing this heatsink with just one of the two fans was not a good option, cooling-wise, except at >9V. Below that, it really can’t keep the CPU cool enough.


When judged on noise vs. cooling, it fares reasonably well against other stock heatsink/fan combinations SPCR has tested. Here’s a quick comparison against a few heatsinks with stock fans at around 23 dBA@1m.

Comparison: With Stock Fans at 12V
°C rise
Zalman CNPS9300 AT
24 dBA
Cooler Master Hyper N520
23 dBA
Xigmatek HDT-SD964
21 dBA
Thermaltake MaxOrb
24 dBA

The slightly smaller Xigmatek HDT-SD964 is the closest competitor, and if the SPL levels were equalized, the Hyper N520 would probably lose by a nose… or degree or dB. It also loses in price, the Xigmatek selling for only around $30, complete with fan.

How close are any of the above to the best reference quality silent coolers? Not very. Almost any one of the top 120mm fan coolers stomps over them all. Here are some of the best:

°C rise of Top 120mm fan CPU Coolers
Nexus 120 fan voltage / SPL @1m
16 dBA
13 dBA
12 dBA
11 dBA
Scythe Ninja 2
Xigmatek HDT-S1283
Thermalright U120E
Noctua NH-U12P
Thermalright HR-01+
Prolimatech Megahalems
All results generated with our reference Nexus 120mm

Why compare the N520 against the best? Because the price difference between them and the $45~50 Cooler Master Hyper N520 is very small. The Ninja 2, for example, sells for $40~50 with its own very quiet fan. The Xigmatek HDT-S1283 runs just $35~40, again, with a fan.


These recordings were made with a high
resolution, lab quality, digital recording system
inside SPCR’s
own 11 dBA ambient anechoic chamber
, then converted to LAME 128kbps
encoded MP3s. We’ve listened long and hard to ensure there is no audible degradation
from the original WAV files to these MP3s. They represent a quick snapshot of
what we heard during the review.

These recordings are intended to give you an idea of how the product sounds
in actual use — one meter is a reasonable typical distance between a computer
or computer component and your ear. The recording contains stretches of ambient
noise that you can use to judge the relative loudness of the subject. Be aware
that very quiet subjects may not be audible — if we couldn’t hear it from
one meter, chances are we couldn’t record it either!

The recordings start with 7~10 second segments of room ambiance, then the fan
at various levels. For the most realistic results, set the volume so that
the starting ambient level is just barely audible, then don’t change the volume
setting again.


The Cooler Master Hyper N520 delivers good enough cooling performance, but its noise level is not really ideal for silent computing. There are positive aspects to its design, including the secure, not-too-tedious installation, the ability to point the fan airflow in any direction with either Intel or AMD motherboards, and nice quality finish. The offset, dual-fan, push-pull design is interesting, as well. It’s difficult for us to get excited by it, however, due to the poor sonic quality of the fans, and the mediocre performance when the fans are slowed for lower noise. This is not to say many others aren’t also similarly noisy; we don’t get excited by them either.

It’s not small enough that the smaller size is much of an advantage over larger, but much higher performance 120mm fan coolers, the dual-fan configuration seems easily matched by a smaller single 92mm fan fan design like the Xigmatek HDT-SD964, and finally, the price is just too high. There have been better CPU coolers from Cooler Master, and there will be again.

Cooler Master Hyper N520

* Good cooling performance at >9V
* Secure mounting system
* Nice fit and finish

* Fan direction controllable with both Intel and AMD socket boards.


* Price
* Not much smaller than better 120mm fan heatsinks
Cooling not good enough for price
* Fans have bad acoustics

Our thanks to Cooler Master for the Hyper N520 sample.

* * *

Articles of Related Interest
Xigmatek HDT-SD964

Thermaltake BigTyp 14Pro: A Bigger Typhoon

Zalman CNPS9900 LED: The End of the

ThermalTake SpinQ: Unique Blower-fan

Thermolab Baram Blows In
Scythe Ninja 2: Tweaking a Classic
Zalman 9300AT: Not me too, but
me again

* * *

Discuss this article in the SPCR forums.

Silent PC Review is reader-supported. When you buy through links on our site, we may earn an affiliate commission. Learn More

Leave a Comment

Your email address will not be published. Required fields are marked *