The Kühler H20 620 and 920 are self-contained liquid CPU cooling units from Antec (manufactured by Asetek). Hopefully they are improvements over the the first water cooler we reviewed, the Corsair Hydro H50, which was sunk for SPCR audiences by a noisy pump.
July 18, 2011 by Lawrence Lee
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Product
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Antec Kühler H20 620 CPU Cooler |
Antec Kühler H20 920 CPU Cooler |
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Manufacturer
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Street Price
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US$60 | US$100 |
Though mostly known for their cases and power supplies, Antec has been exploring other areas like CPU cooling. As we’ve mentioned in the past, it is difficult for a manufacturer to grab a foothold in this space with so many established brands and numerous high-performance models. For every Prolimatech that seems to come out of nowhere to become a big player, there are dozens that come and go before even being noticed by the majority of the DIY community.
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Antec carries a few traditional heatsinks under the “Kühler” name (German for “cooler”) but they also have two self-contained liquid cooling units, the H20 620 and H20 920. They’re not the first to release such products, but it’s still a nice change from the countless tower heatsinks that we come across. We’ve seen so many similar units that they blur and blend together.
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Both units feature a small heat exchanger that is mounted to the CPU, a radiator that is secured to a 120 mm fan placement, and 13″ tubes that carry water. The 920 is the more expensive model, being significantly larger, with two 120 mm fans to the 620’s one, and includes a fan/LED controller that communicates to the system through an internal USB cable.
They resemble members of the Corsair Hydro family which is not surprising given they share the same OEM manufacturer, Asetek. In fact the Kühler H20 920 and Corsair Hydro H70 look like carbon copies of each another except for the tubing; the Kühlers’ tubes are not corrugated, making them more flexible. We reviewed the Hydro H50 last year but were disappointed by the noise level of the pump. Hopefully Antec’s units don’t suffer from this problem.
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Feature & Brief
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Our Comment
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| CPU Socket Compatibility: – Intel LGA 775 / 1155 / 1156 / 1366 – AMD AM2 / AM3 / AM2+ / AM3+ |
As one would expect. |
| Non-corrugated easy-bend tubes for maximum flexibility in radiator positioning | Should make it easier to handle than the Corsair H50. |
| Cooling Liquid – Safe, environmentally-friendly, anti-corrosive | Good to know. |
| Low profile pump ensures exceptional liquid circulation while preserving internal airflow | An advantage in smaller cases. |
| Latest generation copper cold plate for optimal conduction | Standard. |
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Kühler H20 920 Only Features
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| Included software provides essential tools to control and monitor the KÜHLER H2O 920 | The 920 is the first cooler we’ve encountered that ships with fan control software. |
| Pulse Width Modulation (PWM) radiator fans generate the quietest high performance cooling | PWM control allows for lower fan speeds. |
| Customizable RGB LED creates brilliant illumination | Surely a must-have feature. |
| Model | Kühler H20 620 | Kühler H20 920 |
| Fan Speed: | 1450 – 2000 RPM | 700 – 2400 RPM (PWM controlled) |
| Tubing Length | 13.0″ / 330 mm | 13.0″ / 330 mm |
| Radiator Dimensions | 5.6″ (H) x 4.7″ (W) x 1.1″ (D) / 151 mm (H) x 120 mm (W) x 27 mm (D) |
5.6″ (H) x 4.7″ (W) x 1.9″ (D) / 151 mm (H) x 120 mm (W) x 49 mm (D) |
| Fan Dimensions | 4.7″ x 1.0″ / 120 mm x 25 mm | 4.7″ x 1.0″ / 120 mm x 25 mm |
| Air Flow | 81.3 CFM | 110.0 CFM |
| Noise Level | 27 dBA | 43 dBA |
| Cold Plate + Pump Height | 1.1″ / 27 mm | 1.1″ / 29 mm |
| Net weight | 1.5 lbs / 0.7 kg | 2.4 lbs / 1.1 kg |
| Warranty | Antec Quality 3 year limited warranty on parts and labor | Antec Quality 3 year limited warranty on parts and labor |
PHYSICAL DETAILS
The Antec Kühler H20 620/920 is composed of a large copper base attached with multiple screws to a thin plastic cup-like structure (presumably containing a miniature pump and reservoir), two 13″ tubes, and a large radiator that mounts on a standard 120 mm fan placement. Physically the only difference between the two is size; the 920’s radiator is 22 mm thicker and the heat exchanger is also taller by 2 mm.
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INSTALLATION
The most critical aspect of installation is that the heatsink be securely
mounted. A firm mating results in good contact between the heatsink’s base and
the CPU heatspreader and more efficient heat conduction. Ideally it should
also be a simple procedure with the user having to handle as few pieces of
hardware as possible.
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TESTING
Testing on larger heatsinks are done on our
i7-1366 heatsink testing platform, while smaller coolers tackle our AM3 heatsink testing platform. A summary of the test system
and procedure follows.
Key Components in LGA1366 Heatsink Test Platform:
Key Components in AM3 Heatsink Test Platform:
The systems are silent under the test conditions, except for the CPU cooling
fan(s).
Normally, our reference fans are used whenever possible, the measured details
of which are shown below.
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Reference Noctua 140mm fan
Anechoic chamber measurements |
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Voltage
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SPL@1m
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Speed
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12V
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28~29 dBA
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1250 RPM
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9V
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21 dBA
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990 RPM
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7V
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15~16 dBA
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770 RPM
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6V
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13 dBA
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660 RPM
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Reference Nexus 120mm fan
Anechoic chamber measurements |
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Voltage
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SPL@1m
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Speed
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12V
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16 dBA
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1100 RPM
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9V
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13 dBA
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890 RPM
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7V
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12 dBA
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720 RPM
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Reference Nexus 92 mm fan
Anechoic chamber measurements |
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Voltage
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SPL@1m
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Speed
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12V
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16 dBA
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1470 RPM
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9V
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12 dBA
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1150 RPM
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Measurement and Analysis Tools
Noise measurements are made with the fans 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 Prime95 or CPUBurn to stress the processor, and the
graph function in SpeedFan was used to ensure that the load temperature is stable
for at least ten minutes. The temperature recorded is the highest single core
reading. The stock fans were tested at various voltages to represent a good
cross-section of airflow and noise performance.
The ambient conditions during testing were 10~11 dBA and 21~23°C.
Stock Noise Levels
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Antec Kühler H20 620/920 Pump Measurements
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Voltage
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SPL@1m
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H20 620
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H20 920
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12V
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16 dBA
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20 dBA
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9V
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14 dBA
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17~18 dBA
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7V
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12 dBA
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16 dBA
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Measuring mic positioned 1m at diagonal angle from
a point equal-distant between the pump and the fan(s). Ambient noise level: 10~11 dBA. |
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The lower-end 620 ships with just a single lower speed fan and a thinner radiator compared to the 920, but it also has a quieter pump that measures just 16 dBA at 12V to the 920’s 20 dBA at one meter’s distance, making it the better candidate for low noise operation. That being said they both sounded worse than a typical case fan generating the same SPL. 620’s pump emits a low pitched constant buzzing while the 920 produces an irregular but sharper rattle. The volume diminishes as the pump voltage is lowered but the underlying tonality always remains. Editor’s Note: Keep in mind that the pumps are not recommended to be run at below 12V. However, we have not seen any signs of damage or other ill effects from undervolting the pump.
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Specifications: Antec Kühler H20 620 (920) Stock Fans
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Manufacturer
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Power Rating
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? | |
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Model Number
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?
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Airflow Rating
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81.3 CFM (110 CFM) |
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Bearing Type
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Speed Rating
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2000 RPM (2400 RPM) |
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Corners
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Closed |
Noise Rating
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27 dBA (43 dBA) |
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Frame Size
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120 x 120 x 25 mm |
Header Type
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3-pin (4-pin PWM) |
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Fan Blade Diameter
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113 mm |
Starting Voltage
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3.5 V (5.2V) |
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Hub Size
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43 mm |
Weight
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140 g (150 g) |
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Data in green cells provided by the manufacturer
or observed; data in the blue cells were measured. |
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The 620 ships with a seven-blade 2000 RPM 3-pin fan while the larger 920 comes with a pair of nine-blade 2400 RPM 4-pin models. Being such high speed models, they are exceedingly loud at full blast, though their acoustics are dominated mainly by turbulence. Under 1000 RPM, they sounded fairly smooth with a bit of a buzzy character. The buzzing might be the result of the poorly angled struts, positioned almost parallel to the trailing edges of the fan blades.
The 4-pin model doesn’t take well to non-PWM control as its starting voltage is just about 5V; below 6V, adjusting by increments of just 0.1V result in big RPM changes. The 920 has a software fan control system which could make this a non-issue.
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Antec Kühler H20 620 Stock Fan Measurements
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Voltage
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Speed
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SPL@1m
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Fan Only
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Fan & Pump
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12V
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1920 RPM
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33 dBA
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33 dBA
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9V
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1550 RPM
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27 dBA
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27~28 dBA
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7V
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1270 RPM
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21~22 dBA
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22 dBA
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6V
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1110 RPM
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18 dBA
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20 dBA
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5V
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940 RPM
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14 dBA
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19 dBA
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Measuring mic positioned 1m at diagonal angle from
a point equal-distant between the pump and the fan(s). Ambient noise level: 10~11 dBA. |
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Antec Kühler H20 920 Stock Fan Measurements
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Voltage
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Avg. Speed
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SPL@1m
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Fans Only
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Fans & Pump
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12V
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2360 RPM
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48~49 dBA
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48~49 dBA
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9V
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1930 RPM
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42 dBA
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42 dBA
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7V
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1470 RPM
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31~32 dBA
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32 dBA
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6V
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1190 RPM
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26 dBA
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26~27 dBA
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5.6V
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840 RPM
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17 dBA
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22 dBA
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Measuring mic positioned 1m at diagonal angle from
a point equal-distant between the pump and the fan(s). Ambient noise level: 10~11 dBA. |
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As the 620’s pump measures 20 dBA at 12V compared to the 33 dBA for the stock fan, it’s probably best to control the two separately rather than driving them off a single fan header. At 7V and above, the fan drowns out the pump, so the pump might as well be run at full speed. There’s a similar mismatch with the 920, but it has an even smaller range of fan speeds where the pump actually makes an acoustic impact. We do plan on adjusting the voltage to the pump during testing, but it only seems worthwhile with the fan at 6V and below.
Kühler H20 920 Software
The fancier dual fan 920 ships with the “Chill Control V” software which allows users to monitor and adjust the fan and pump speeds via an internal USB connector.
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The main dashboard has temperature as well as fan and pump speed read-outs. A noise readout is also included but it is completely inaccurate. It might be based on based on the fan and pump speeds but it’s either a complete gimmick or calibrated poorly as 8 dB is impossible at any speed other than 0 RPM.
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The software also offers graphing functions and a rudimentary custom fan control menu with starting and full speed temperatures.
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Of course an enthusiast PC cooling device is not complete without LED control. Yes, for US$100, you get a thick high enclosed water cooler, a fan control system, and the LEDs lighting up the Antec name on the heat exchanger can be adjusted to a custom RGB level. If you’re feeling festive, the boring blue light can be changed to pink with a few mouse clicks and keystrokes.
Cooling Results
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Antec Kühler H20 620
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Voltage
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Thermal Rise
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SPL @1m
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Fan
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Pump
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Stock 120mm Fan
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12V
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12V
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37°C
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33 dBA
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9V
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39°C
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27~28 dBA
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7V
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42°C
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22 dBA
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6V
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44°C
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20 dBA
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7V
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44°C
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18~19 dBA
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5V
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12V
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47°C
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19 dBA
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7V
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47°C
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16 dBA
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Reference 120mm Fan (Nexus)
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12V
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12V
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41°C
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20~21 dBA
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9V
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45°C
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20 dBA
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7V
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47°C
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19~20 dBA
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9V
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12V
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46°C
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17 dBA
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9V
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48°C
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16 dBA
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7V
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51°C
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15~16 dBA
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7V
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12V
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52°C
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16 dBA
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9V
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52°C
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14 dBA
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7V
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53°C
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13 dBA
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The Kühler 620 performed very well at high fan speeds producing a thermal rise under 40°C (excellent for our test platform); however, noise levels were very high. With the stock fan slowed to produce 20 dBA@1m or lower, the thermal rise increased to 44~47°C. The pump speed had no impact in performance when coupled with the fan running at 6V and below (above that level the pump starts to get drowned out, so you might as well leave it running at max).
Our reference Nexus fan on the other hand was very much dependent on the pump speed to achieve good results. With the fan speed at 12V and 9V, temperatures were 5~6°C higher when the pump was undervolted from 12V to 7V. When the fan became the performance bottleneck at 7V as the speed of the pump had almost no effect. Overall our reference fan performed on par with the stock model at comparable noise levels..
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Antec Kühler H20 920
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Voltage
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Thermal Rise
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SPL @1m
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Fan
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Pump
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Stock 120mm Fans
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12V
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12V
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33°C
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48~49 dBA
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9V
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34°C
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42 dBA
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7V
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36°C
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32 dBA
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6V
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38°C
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26~27 dBA
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5.6V
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41°C
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22 dBA
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7V
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41°C
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19 dBA
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Reference 120mm Fans (Nexus)
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12V
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12V
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40°C
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25 dBA
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7V
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41°C
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23 dBA
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9V
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12V
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43°C
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23 dBA
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7V
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44°C
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18~19 dBA
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7V
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12V
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48°C
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22 dBA
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7V
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48°C
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17 dBA
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The Kühler H20 920, given its larger size and two fans, gave us similar results, excelling primarily at higher fan speeds. It kept things noticeably cooler when the pump and fan were slowed to generate less than 20 dBA@1m though. Once again, undervolting the pump didn’t have any negative consequences when using the stock fans.
The pump’s speed was also a non-factor with our reference Nexus fans as there was a 1°C difference at most when the pump’s voltage was decreased to 7V. On the 920, the stock fans excelled, producing lower temperatures at similar noise levels. This is surprising given their history of superiority over the stock fans of most tested heatsinks. It seems the stock fans are well suited for cooling down the tight fin spacing of the 920’s radiator.
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Comparisons
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Liquid CPU Coolers: °C Rise Comparison (pump at full speed)
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Cooler
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SPL (dBA@1m)
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24
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23
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22
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21
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20
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Corsair Hydro H50
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44
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–
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47
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–
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Antec Kühler H20 620
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–
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–
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42
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–
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44
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Antec Kühler H20 920
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–
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–
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41
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–
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–
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Compared to the Hydro H50, both Kühlers come out smelling like roses. When generating around 22 dBA@1m, the 620 and 920 run 5°C and 6°C cooler respectively. This is due in large part to their quieter pumps which allow for higher fan speeds.
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Single Fan CPU Coolers (ref. 120mm fan): °C Rise Comparison
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Heatsink
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Fan voltage / SPL @1m
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12V
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9V
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7V
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16 dBA
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13 dBA
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12 dBA
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Thermalright Ultra-120 eXtreme Rev.C
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38
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40
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43
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Thermalright Venomous X
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38
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41
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43
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Prolimatech Megahalems
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38
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41
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44
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Noctua NH-U12P
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39
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42
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44
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Scythe Mugen-2
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39
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42
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45
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Cogage TRUE Spirit 1366
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40
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42
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45
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Prolimatech Armageddon
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40
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42
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46
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Zalman CNPS10X Quiet
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40
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43
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46
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Scythe Yasya
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41
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43
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47
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Thermalright Ultra-120 eXtreme
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40
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43
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48
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Cooler Master Hyper 212 Plus
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41
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44
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48
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Thermalright Ultra-120
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42
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45
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49
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Titan Fenrir
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43
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46
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50
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Scythe Ninja 3
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44
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47
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49
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Noctua NH-C12P
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43
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47
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51
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Zalman CNPS10X Extreme
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43
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47
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53
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Swiftech Polaris 120
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46
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49
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54
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Zalman CNPS10X Flex
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45
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50
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54
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Cooler Master V8
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46
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50
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54
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Scythe Grand Kama Cross
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45
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52
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57
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Antec Kühler H20 620
(stock fan, pump at 7V) |
47
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Arctic Cooling Freezer Xtreme Rev.2
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49
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52
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58
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Scythe Kabuto
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51
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53
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60
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The Kühler 620 fares quite poorly against the majority of single 120 mm fan tower heatsinks. At 16 dBA@1m (stock fan at 5V, pump at 7V) it produced a thermal rise of 47°C which places two spots ahead of last just above the Freezer Xtreme Rev.2.
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°C Rise Comparison vs. Dual Fan 140 mm Coolers (reference fans)
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Heatsink
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Fan Voltage / SPL*
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8V
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7V
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6V
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18~20 dBA
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15~17 dBA
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12~14 dBA
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Prolimatech Genesis
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36
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37
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39
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Noctua NH-C14
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37
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39
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41
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Thermalright Silver Arrow
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37
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39
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41
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Noctua NH-D14
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38
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40
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42
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Thermalright Venomous X
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39
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41
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42
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NZXT Havik 140
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39
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40
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43
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Antec Kühler H20 620 (stock fan, pump at 7V)
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44
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47
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*Note: there are minor differences in measured SPL due to the variety of fan orientations and mounting methods offered by the compared coolers.
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In a showdown against top-end dual fan heatsinks, the Kühler 920 doesn’t do very well either, achieving results 5~7°C higher than the NZXT Havik 140.
Now undoubtedly we will be inundated with comments about how these water cooling systems perform much better inside a case. You can also make the argument that these closed loop liquid coolers take up a 120 mm fan placement which could otherwise be used by a system exhaust fan which would give air-cooled heatsinks a leg up. We don’t test to see how coolers perform in one particular case layout with fans A, B, and C helping out, but how they perform against one another in as pure a form as possible. Our open testbed was deliberately chosen to eliminate these variables from the cooling equation.
MP3 SOUND RECORDINGS
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 recording starts with 5~10 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.
FINAL THOUGHTS
The Antec Kühler H20 620/920 is a big improvement over the first fully-assembled one piece CPU water cooler we reviewed, the Corsair Hydro H50. The pumps on both units are considerably quieter, particular on the 620. This allows Kühler users to run their fans faster and produce better temperatures at similar noise levels to the H50. The smooth, non-corrugated tubing also gives them greater flexibility than the stiff plastic hoses of the Hydro series.
Despite these improvements, our final tests results were not compelling. Neither managed to match the majority of comparably priced tower coolers on our heatsink test platform. Given its street price of about US$60, the 620’s main competition are premium single 120/140 mm fan heatsinks. Of the 22 we’ve tested in the past couple of years, 20 of them outperformed the 620. The larger 920, with its thicker radiator, second fan, and fan/LED controller goes for US$100, making it fair game for expensive dual 14 cm fan coolers. We’ve reviewed only six of these beasts but they all outpaced the 920 by a large margin.
These units are popular amongst DIY enthusiasts who can’t afford or lack the technical expertise or dedication to construct a proper water cooling system, but from what we’ve seen so far, they just aren’t efficient enough. The Kühler H20 620/920, even though they have quieter pumps than the H50, are still handicapped by the additional noise source of the pump, making them impossible to succeed as super-quiet CPU coolers. When you consider the risk of leaking liquid into your system and the countless number of superior alternatives that don’t have this potential liability, it only makes sense to use them in cases with limited CPU heatsink clearance. Small microATX cases with 120 mm fan placements like the Silverstone GD05 and Lian Li PC-V354 come to mind. For performance oriented silencers, stick to tried and true air coolers. They are both cheaper and more effective.
Our thanks to Antec for the Kühler H20 620/920 CPU cooler samples.
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Articles of Related Interest
Havik 140: NZXT’s First CPU Heatsink
Thermalright Venomous X Silent Edition CPU Cooler
Prolimatech Genesis CPU Heatsink: Retaking the Crown
Swiftech Polaris 120 CPU Heatsink
Zalman CNPS9900 MAX & CNPS5X CPU Coolers
Corsair Hydro H50 CPU Water Cooler
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