Author: Jani 'Japala' Pönkkö
Published: 10.07.2002
Manufacturers: Thermalright
Product group: Coolers
 Thermalright SK-6
 Coolermaster HSC-V62
 Coolermaster HHC-L61
 Bitspower NP81DS20
 Bitspower NP18MCS
 Benchmark & results

Socket cooler roundup

NP18MCS, SK-6, NP81DS20, HHC-L61 and HSC-V62

This time we will be reviewing five different socket coolers.

SK-6HSC-V62 and HHC-L61NP81DS20 and NP18MCS

I tried to gather coolers that are not so loud but are still good performers. Hope that we can determine what feature gives the best results. Heat pipe, size in general, cfm rating etc. Lets go and meet our contenders.




Thermalright SK-6


SK-6 is an all copper cooler. Fins are soldered to the base plate. Fan is attached with the help of two wire clips. Clips were easy to install and to remove. This way it's fast and easy to try different fans to this cooler.

Technical specifications:

Dimensions L64 x W72 x H31.6 (mm) -- Top
L64 x W64 x H31.6 (mm) -- Bottom
Weight 330 g

This cooler can be supplied with different fans. I decided to test it with Sunon GM1206PTVX-A because it seemed like a reasonable performer with a reasonable sound levels.

Specs for the fan:

Voltage 12
Current 0.23 A
Input watts 2.8
Speed RPM 5200
Airflow CFM 26.2
Noise dBA 38

Clip of SK-6

Base of SK-6

Clip of the SK-6 was very easy to work with. It has a bent "pin" that you can use with your screw driver. Clip is firm but you don't need any excess power when installing it.

Base of the cooler was smooth and polished. Good quality work.


Coolermaster HSC-V62


HSC-V62 is a all new cooler that is also full copper with skived fins. Special about this cooler is that it uses a smart thermal sensor in it's fan to control fan speed. This ensures that the fan is running with just a right speed. Sensor is placed directly under the motor so it is not affected by the air flow and thus giving more accurate readings. The fan is configured to follow special Speed vs. temp graph:

Speed vs. temp

Technical specifications:

Voltage 12
Heat sink dimensions 60 x 60 x 29 mm
Fan dimensions 60 x 60 x 25 mm
Speed RPM 3000 ~ 6800
Airflow CFM 16.13 ~ 36.11


Base plate is 5 mm thick and contains 36 skived fins meaning that this cooler is cutted from a one block of copper. No solders that could affect the cooling.

Clip of HSC-V62

Base of HSC-V62

Here is the clip design that should be a standard for every cooler. No tools needed and it's even more easier to work with than SK-6's clip. Just press the clip with you thumb and slide it to its place.

Base of this cooler was really smooth and polished. No machining lines visible and it was protected with a sticker that covered the whole base. Good thinking there.


Coolermaster HHC-L61


Another product from Coolermaster is HHC-L61. It uses the heat pipe technology to transfer heat from the base to the upper parts of the fins where the fan can then remove it more effectively. In this cooler there are two heat pipes. Both filled with a liquid that will get vaporized when the base heats up. Vapor will then travel the tubes to the fan. Fan will then cool the vapor down and it will transform back to the liquid state and drain back to the base to start the cycle again.

Technical specifications:

Voltage 12
Heat sink dimensions 80 x 60 x 44 mm
Fan dimensions 60 x 60 x 25 mm
Speed RPM 3000
Airflow CFM 14.13


Clip of HHC-L61

Base of HHC-L61

This cooler uses the same brilliant clip design as HSC-V62. Hope that the other manufacturers will notice how simple, yet effectice this design is.

Again the base was really smooth as with HSC-V62. The base was also protected with a thick sticker. As you can see from the image, the cooler has a quite large footprint. This may be a problem with some motherboards as those heat pipes might get in the way.


Bitspower NP81DS20 (Super Silence)


NP81DS20 is a skived-fin all-aluminium cooler. You immediately notice how big this cooler is. Footprint is actually quite small because the cooler widens to the top. This also allows the usage of 80x80 mm fans. By using larger fan this cooler is virtually silent. The fan is rated to 2000 RPM and 30 CFM so it's a great performer compared to other fans in this review.

Technical specifications:

Weight 350 g
Heat sink dimensions L80 *W60 *H45 mm
Fan dimensions L80 *W80 *H25 mm
Speed RPM 2000
Airflow CFM 30
Noise dBA 23.5
Rated input 1.2 W


Clip of NP81DS20

Base of NP81DS20

This is the only cooler in this test that has a clip with three holes on each side. This really nails the cooler to its place and there is no worry that you will ruin your socket while installing this. You also notice that there is this bent pin again to assist you while installing the clip with a screw driver. As with the SK-6, you don't need to use any excess power to force the clip to its place.

Base of the cooler is relatively smooth. You can notice same scratches but with the help of good quality thermal grease it shouldn't be a real problem. Maybe something that Bitspower should look into in a future.


Bitspower NP18MCS


NP18MCS is a all-copper skived-fin cooler with a very powerfull but low profile fan. When you look at it, it almost seems like that this is only ment to be used with low power rack machines. When you pick it up you'll notice that it feels really heavy. Maybe because it's so small and other this kind of coolers doesn't usually weight as much.

The cooler has 46 fins. This to ensure proper transfer of heat while the fins itself are quite low. This might also become a weak spot of this cooler. The fins are so close to each other so they will need properly filtered air so they don't get filled with all the dust and particles that are flying around your household.

Technical specifications:

Weight 300 g
Heat sink dimensions L60 *W60 *H18 mm
Fan dimensions L60 *W60 *H15 mm
Speed RPM 5300 ±10 %
Airflow CFM 24.5
Noise dBA 40
Rated input 3.48 W


Clip of NP18MCS

Base of NP18MCS

Let's talk about the clip. What a horror. It only has two bent pins on the sides. This means that you need a screw driver with an exact width to fit between them. If you use too small screw driver, it will not hold properly and you are likely to hit your motherboard. Don't really understand why there isn't any protection like in these few other coolers that are reviewed here. It only needs a small pin like in SK-6 to ensure that the screw driver will not slip. I sure hope that they will do something about this.

What a shine. There is absolutely nothing bad to be said about the base of this cooler. Smooth and polished like it should be.




Testing method

Heating platform

I made a test platform to be used in this review. This to make sure that I can control the environment where the test is to be executed and to monitor the performance of the cooler without outside interference from case coolers etc.

The platform consists of two power resistors that can withstand 50 watts of power per unit without any additional cooling. With additional cooling this system can be used to test coolers with combined power well over 150 watts. Modern day CPUs can have heat dissipation of 75 watts or even more but for this test the system will be used to dissipate 86 watts. Higher power is used because the resistors will radiate the heat around and not to focus it to one point. Also there is a piece of copper that is used to simulate CPU core and these additional surface contact points will affect the transfer of the heat. I used a good quality silver grease in every cooler. This to ensure fair comparision between coolers and not between their thermal compounds.

TES 1322

To measure the temperature I used a TES 1322 infrared & K thermometer. Thermocouple was placed between the resistors and directly beneath the simulated CPU core.



I recorded temperature readings in 5 second intervals. This to make a nice graph where one can see how the coolers performed when they were given that full load. I recorded the temperatures as long as they were rising or falling and then waited for 10 additional minutes to take the final reading. I made this test two times for each of the coolers and took average from both measurements.

This is how it all sums up:


Final results

  SK-6 NP81DS20 NP18MCS HSC-V62 HHC-L61
Temperature 69.3 78.7 66.9 77.1 78.2
Sound level Above average Silent Above average Almost silent Silent

When you look at the graph you have to remember that these number are closer to the numbers that you could receive from the thermal diode inside your processor. Many times temperatures are read from the socket's thermal sensor. That temperature is a lot lower than temperature inside the CPU. Because the thermal sensor is between the resistors these numbers resemble that inner temperature.


Interpreting the results

As you can see from that graph, Bitspower's NP18MCS and Thermalright's SK-6 were the best performers. This is quite amazing. NP18MCS were the smallest of all the coolers and it outperformed them all. Maybe this has something to do with the fact that the fan of the NP18MCS had the highest power rating of all.

One could improve the performance of every cooler here by replacing the fan. This could be especially noticeable with Coolermaster coolers. As you notice, they both were really quiet and thus they are not so powerfull as many other fans. This is also something that I wanted to point out with this review. Not all coolers should be the highest performers with the highest RPM fans. You can manage just fine with a good quality cooler that has a low RPM fan that doesn't produce that much noise pollution. At least this review proved that silent coolers are up to the task with the highest powered CPUs. At least for now.



Thermalright SK-6
A great performer with reasonable amount of noise. I currently use this cooler on my AMD 1800+ system and internal diode shows temperatures of 60°C in idle state and around 67°C while gaming. This alone proves that our test was successfull and correlated the real life situation. Clip of the SK-6 is well designed and the wire clips that hold the fan are simple in design but keep the fan in place really tight.
Coolermaster HSC-V62
The fan of HSC-V62 uses a new technique where the thermal sensor is placed directly below the fan motor. From the graph you can see that temperature almost hit 80°C before it started to come down. This rise isn't that alarming because the fan followed that Speed vs. Temp. graph quite well and the fan started taking more RPMs as soon as the temperature rose. Fan itself was really quiet although you could notice when the fan increased those RPMs. Clip of the HSC-V62 is something that every manufacturer should learn from. You don't need any tools so there is no risk of you harming your socket or motherboard while installing this.
Coolermaster HHC-L61
This cooler is for everyone that doesn't like to hear any additional noises from his/hers comp. The fan was extremely silent. This was also a problem. With fan pushing only 14.13CFM of air it was really noticable that the heat wasn't getting out from the cooler properly. Surrounding area near the cooler was really hot and the air didn't move. Could become a problem with cases that have poor air circulation. If clip design is to be compared, this cooler gets the top place. And what about design? This cooler looks really great via the case window.
Bitspower NP81DS20
The only aluminium cooler in this review. NP81DS20 was the worst performer if you look only the temperature but you have to remember that this cooler has 80x80 mm fan rotating only at 2000RPM so it is virtually silent. I actually didn't expect this cooler to perform this well against these copper coolers but it did a reasonable job. This was also the only cooler that used all the three hooks from the socket. This reduces the strain and this way you can expect your socket to last longer.
Bitspower NP18MCS
Looks very small and not so powerfull but you really shouldn't judge coolers only by their looks. Best performer with reasonable amount of noise. Only real downside being the clip design. You can change the clip from some other cooler but let's hope that Bitspower will change the clip design to something more functional. Low profile means that you can use this for you rack cases or with some custom case building projects where you might need smaller cooler for the CPU. This cooler was a great move from Bitspower. Small, yet extremely powerfull.


I would like to thank all the manufacturers for sending these products for reviewing.

Additional information

Coolermaster Bitspower Thermalright

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