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[nextpage title=”Introduction”]

The Kühler H2O 620 is a sealed liquid CPU cooling system from Antec. Let’s test it and check its performance.

The Kühler H2O 620 is actually manufactured by Asetek, which also makes watercoolers for Corsair- such as the H70; which we already reviewed. Even though the Kühler H2O 620 resembles the Corsair H50, they are not exactly the same product.

The product box is large and has no openings. See Figure 1.

Antec Kühler H2O 620 Figure 1: Package

Figure 2 illustrates what is inside the box: a premounted and sealed block-pump-hoses-radiator system, a 120 mm fan, manual, and installation hardware.

Antec Kühler H2O 620 Figure 2: Accessories

In Figure 3, you can see the Antec Kühler H2O 620.

Antec Kühler H2O 620 Figure 3: The Kühler H2O 620

This watercooler is discussed in detail in the following pages.

[nextpage title=”The Kühler H2O 620″]

Figure 4 shows the CPU block into which the pump is integrated.

Antec Kühler H2O 620Figure 4: CPU block

Figure 5 reveals base of the block. It is made of copper and comes with thermal compound applied. Note the two cables on the block: one must be connected to the motherboard in order to power the system; the other one powers the radiator fan- so that the circuitry at the block can control the speed of the fan.

Antec Kühler H2O 620Figure 5: Base

In Figures 6 and 7 you see the radiator, which must be installed at a 120 mm fan opening at the rear of the case.

Antec Kühler H2O 620Figure 6: Radiator

Antec Kühler H2O 620Figure 7: Top view

In Figure 8 is the 120 mm fan that comes with the H2O 620. Its cable is short because it is not intended to be connected to the motherboard but to the block wire, as we already mentioned.

Antec Kühler H2O 620Figure 8: Fan

[nextpage title=”Installation”]

In Figure 9, you see the clip used to install the Kühler H2O 620 on Intel CPUs. The AMD clip is very similar to this one. The backplate shown at the right goes on the solder side of the motherboard, and the metal frame at the left goes on the component side and holds the block.

Antec Kühler H2O 620Figure 9: Intel clip

Figure 10 shows the mounting system in place. This frame supports sockets 775, 1155, 1156, and 1366 CPUs.

Antec Kühler H2O 620Figure 10: Intel frame installed

In Figure 11, the Kühler H2O 620 is installed in our computer. Note that the fan is placed between the radiator and the case rear panel, so a second fan can be installed at the other side of the radiator.

Antec Kühler H2O 620Figure 11: Installed in our system

[nextpage title=”How We Tested”]

We tested the cooler with a Core i7-860 CPU (quad-core, 2.8 GHz), which is a socket LGA1156 processor with a 95 W TDP (Thermal Design Power). In order to get higher thermal dissipation, we overclocked it to 3.3 GHz (150 MHz base clock and 22x multiplier), keeping the standard core voltage (Vcore), which was the maximum stable overclock we could make with the stock cooler. Keep in mind that we could have raised the CPU clock more, but to include the stock cooler in our comparison, we needed to use this moderate overclock.

We measured noise and temperature with the CPU idle and under full load. In order to get 100% CPU usage in all threads, we ran Prime 95 25.11 with the "In-place Large FFTs" option. (In this version, the software uses all available threads.)

We compared the tested cooler to the Intel stock cooler with a copper base (included with the CPU), as well as with other coolers. Note that in the past, we tested coolers with a socket LGA775 CPU, and we retested some "old" coolers with this new methodology. This means you can find different values in older reviews than the values you will read in the next page. Every cooler was tested with the thermal compound that accompanies it.

Room temperature measurements were taken with a digital thermometer. The core temperature was read with the SpeedFan program (available from the CPU thermal sensors), using an arithmetic average of the core temperature readings. During the tests, the left panel of the case was open.

The sound pressure level (SPL) was measured with a digital noise meter, with its sensor placed 4" (10 cm) from the fan. We turned off the case and video board cooler fans so they wouldn’t interfere with the results. This measurement is only for comparison purposes, because a precise SPL measurement needs to be made inside an acoustically insulated room with no other noise sources, which isn’t the case here.

Hardware Configuration

Operating System Configuration

  • Windows 7 Home Premium 64 bit

Software Used

Error Margin

We adopted a 2 °C error margin, meaning temperature differences below 2 °C are considered irrelevant.

[nextpage title=”Our Tests”]

The table below presents the results of our measurements. We repeated the same test on all coolers listed below. Each measurement was taken with the CPU at idle and at full load. In the models with a fan supporting PWM, the motherboard controlled the fan speed according to core load and temperature. On coolers with an integrated fan controller, the fan was set at the minimum speed on the idle test and at full speed on the full load test.


Idle Processor

Processor at Full Load

Cooler Room Temp. Noise Speed Core Temp. Noise Speed Core Temp.
Intel stock (socket LGA1156) 14 °C 44 dBA 1700 rpm 46 °C 54 dBA 2500 rpm 90 °C
Cooler Master Hyper TX3 G1 14 °C 47 dBA 2050 rpm 33 °C 56 dBA 2900 rpm 62 °C
Zalman CNPS10X Extreme 14 °C 45 dBA 1400 rpm 27 °C 53 dBA 1950 rpm 51 °C
Thermaltake Silent 1156 14 °C 44 dBA 1200 rpm 38 °C 49 dBA 1750 rpm 69 °C
Noctua NH-D14 14 °C 49 dBA 1250 rpm 27 °C 49 dBA 1250 rpm 53 °C
Zalman CNPS10X Performa 14 °C 46 dBA 1500 rpm 28 °C 52 dBA 1950 rpm 54 °C
Prolimatech Megahalems 14 °C 40 dBA 750 rpm 27 °C 60 dBA 2550 rpm 50 °C
Thermaltake Frio 14 °C 46 dBA 1450 rpm 27 °C 60 dBA 2500 rpm 50 °C
Prolimatech Samuel 17 14 °C 40 dBA 750 rpm 40 °C 60 dBA 2550 rpm 63 °C
Zalman CNPS8000A 18 °C 43 dBA 1400 rpm 39 °C 54 dBA 2500 rpm 70 °C
Spire TherMax Eclipse II 14 °C 55 dBA 2200 rpm 28 °C 55 dBA 2200 rpm 53 °C
Scythe Ninja3 17 °C 39 dBA 700 rpm 32 °C 55 dBA 1800 rpm 57 °C
Corsair A50 18 °C 52 dBA 1900 rpm 33 °C 52 dBA 1900 rpm 60 °C
Thermaltake Jing 18 °C 44 dBA 850 rpm 34 °C 49 dBA 1300 rpm 60 °C
GlacialTech Alaska 18 °C 43 dBA 1150 rpm 36 °C 51 dBA 1600 rpm 60 °C
Deepcool Gamer Storm 18 °C 43 dBA 1100 rpm 35 °C 48 dBA 1600 rpm 62 °C
Corsair A70 26 °C 56 dBA 1900 rpm 40 °C 56 dBA 1900 rpm 65 °C
Deepcool Ice Blade Pro 23 °C 45 dBA 1200 rpm 38 °C 52 dBA 1500 rpm 64 °C
AC Freezer 7 Pro Rev. 2 23 °C 47 dBA 1750 rpm 44 °C 51 dBA 2100 rpm 77 °C
Corsair H70 27 °C 60 dBA 1900 rpm 37 °C 60 dBA 1900 rpm 61 °C
Zalman CNPS9900 Max 27 °C 55 dBA 1600 rpm 38 °C 58 dBA 1750 rpm 63 °C
Arctic Cooling Freezer 11 LP 25 °C 45 dBA 1700 rpm 51 °C 49 dBA 1950 rpm 91 °C
CoolIT Vantage 26 °C 60 dBA 2500 rpm 37 °C 60 dBA 2500 rpm 62 °C
Deepcool Ice Matrix 600 25 °C 46 dBA 1100 rpm 41 °C 53 dBA 1300 rpm 69 °C
Titan Hati 26 °C 46 dBA 1500 rpm 40 °C 57 dBA 2450 rpm 68 °C
Arctic Cooling Freezer 13 27 °C 49 dBA 1950 rpm 41 °C 53 dBA 2300 rpm 70 °C
Noctua NH-C14 26 °C 52 dBA 1300 rpm 37 °C 52 dBA 1300 rpm 61 °C
Intel XTS100H 26 °C 49 dBA 1200 rpm 42 °C 64 dBA 2600 rpm 68 °C
Zalman CNPS5X SZ 23 °C 52 dBA 2250 rpm 38 °C 57 dBA 2950 rpm 69 °C
Thermaltake SlimX3 21 °C 50 dBA 2700 rpm 46 °C 50 dBA 2750 rpm 99 °C
Cooler Master Hyper 101 21 °C 50 dBA 2600 rpm 38 °C 57 dBA 3300 rpm 71 °C
Antec Kühler H2O 620 19 °C 52 dBA 1400 rpm 34 °C 55 dBA 1400 rpm 58 °C

In the graph below, at full load you can see how many degrees Celsius hotter the CPU core is than the air outside the case. The lower this difference, the better is the performance of the cooler.

 Antec Kühler H2O 620

[nextpage title=”Main Specifications”]

The main features of the Antec Kühler H2O 620 watercooler include:

  • Application: Sockets 775, 1155, 1156, 1366, AM3, AM2+, and AM2 processors
  • Fins: Aluminum
  • Base: Copper
  • Heat-pipes: None
  • Fan: 120 mm
  • Nominal fan speed: 2,000 rpm
  • Fan air flow: 81.3 cfm
  • Maximum power consumption: Not informed
  • Nominal noise level: Not informed
  • Weight: 1.5 lbs (700 g)
  • More information: https://www.antec.com
  • Average price in the US*: USD 80.00

* Researched at Newegg.com on the day we published this review.[nextpage title=”Conclusions”]

The Antec Kühler H2O 620 seemed to be an excellent watercooling system at first sight. It is easy to install, is elegant, and quiet; and it cooled our CPU reasonably well. However, the problem is that you don’t buy a watercooler system to cool your processor "reasonably well". When you buy a watercooler, you are looking for some extra cooling, and this product doesn’t provide it.

So, if you are looking for a watercooler just to know your computer isn’t an ordinary air-cooled one, you can buy the Antec Kühler H2O 620; it is a good product that will not give you headaches. But if you are looking for a good cost/benefit ratio, just forget about it and look for a good air cooler.