Antec Kuhler H2O 620 Water Cooler


Antec Kuhler H2O 620

Antec has been around for as long as I can remember; my very first custom system I built used an Antec case. Now Antec has thrown their hat into the cooling world and one of the offering they have is the Kuhler H20 620. Now, if the Kuhler H20 620 looks familiar you’re not crazy. It’s a team effort between Antec and Asetek, just like the H50/H70 was for Corsair and Asetek, but this last year Corsair moved away from Asetek to CoolIt Systems for their new H60 from their Hydro Series coolers.

Now, before assumptions are made that the Kuhler H2O 620 and the H50 are the same since at first glance it seems they are, but looking closer it is obvious they are not. The Kuhler H2O 620 has the thin radiator like the H50, but the low profile pump and cold plate like the H70. There are also other changes. For instance, the coolant tubing is not corrugated like on the Corsair coolers; the non-corrugated tubing is more flexible making it easier to install and position the radiator. The Kuhler H20 620 also has the newest generation cold plate.

With all the design updates to an already proven design I’m very interested to see how this newest offering performs. Costing $62.95 plus $11.46 shipping directly from Antec’s online shop or $79.99 plus $3.99 shipping from Newegg, the Kuhler H2O 620 is about as inexpensive of a step into water cooling as you can get. It should be noted that Antec is doing a 10% off promotion right now, but either way it is cheaper to buy the cooler directly from them than Newegg.  This came as a shock to us as well, so if you are going to be buying one of these be sure to take note of that!  Let’s take a look at the features and specifications for the Kuhler H2O 620.

Features of the Antec Kuhler H2O 620 CPU

Specifications for the Antec Kuhler H2O 620 CPU


Unboxing The Kuhler H2O 620


Antec Kuhler H2O 620 box front

In Antec style the packing for the Kuhler H2O 620 is a nice blend of marketing and specifications. On the front is a very nice image of the cooler.

Antec Kuhler H2O 620 box top

The top of the box has a small image of the cooler installed along with a short list of features.

Antec Kuhler H2O 620 box end

On one end there is a chart that shows how the Kuhler H2O 620 performs against the stock Intel cooler for an Intel Core i7 980 @3.33GHz. The chart shows roughly a 20*C gain in performance.

Antec Kuhler H2O 620 box end

On the other end is a listing of the Kuhler H2O 620’s specifications and what is included in the box.

Antec Kuhler H2O 620 box back

The back of the box has images of different parts of the cooler and short descriptions of each.

inside the box for the Antec Kuhler H2O 620

Opening the box we can see the unit is held in a formed cardboard tray and has a layer of foam sheet between it and the box side.

Antec Kuhler H2O 620 packing tray

With the tray pulled from the box we can see the cooler and all the accessories are cradled nicely for shipping.

Antec Kuhler H2O 620 mounting hardware

All the mounting hardware is packaged nicely in a double bag arrangement. I like this less likelihood of losing a small part due to a hole in a baggie.

Antec Kuhler H2O 620

The pump/cold plate of the unit comes wrapped in plastic.

Antec Kuhler H2O 620 protected

The cold plate with the pre-applied thermal paste is protected with a plastic shell. The shell holds on to the locking lugs on the pump housing so it will not come off in shipping.

Looking closer at the Kuhler H2O 620


Antec Kuhler H2O 620

The Kuhler H2O 620 is a nice little unit. The hoses are 13 inches and the pump power wire is 12" long. So mounting the radiator and still reaching the CPU socket should not be an issue with most cases. In some small cases there could be an issue with the hoses being too long; same for really huge cases and the hoses being too short to mount the radiator in the top of the case. Mounting to the rear 120mm fan port, the 13” tube length should be just right.

There are two power leads coming from the pump housing. One is for connecting to the motherboard. The other is for connecting to the fan. This means that the Kuhler H2O 620 will only take 1 motherboard fan header. Since the radiator for the Kuhler can accept twin 120mm fans we asked Antec if the fan power lead on the Kuhler could handle powering two 120mm fans. We were told that it is not recommended.

Antec Kuhler H2O 620 pump and cold plate housing

The Kuhler H2O 620 has a nice low profile pump and cold plate housing. The housing is only 1.1” or 27mm tall.

Antec Kuhler H2O 620 90 degree swivel fitting

To aid in installing the kit the tubing is connected to the pump with a 90 degree swivel fitting.

Antec Kuhler H2O 620 soft flexible rubber tubing

The Antec Kuhler H2O 620 also has soft flexible rubber tubing, rather than stiff corrugated tubing. The soft rubber tubing is very flexible and can have a rather tight bend radius. Corrugated tubing is very stiff in comparison, so the flexibility will make it much easier to install.

Antec Kuhler H2O 620 thermal paste

The unit comes with thermal paste pre-applied to the base of the cold plate.

Antec Kuhler H2O 620 cold plate

With the stock paste out of the way we can see the cold plate for the Kuhler H2O 620 has a nice finish to it.

Antec Kuhler H2O 620 120mm radiator side

Like with the H50 the Kuhler H2O 620 has a thin single 120mm radiator. The radiator is only 1” or 25mm thick. When paired with the included fan the mounting thickness is only 2” or 50mm. The radiator is able to have a second fan mounted to it, but the pump housing only has one fan connector and Antec does not recommend using a Y adapter to power two fans, so power will need to be pulled from another source.

Antec Kuhler H2O 620 120mm radiator fins

Looking at the fins the radiator has 21-22 fins per inch. So the more CFM that can be put through it the better. The overall dimension of the radiator is 5.6” (151mm) high and 4.7” (120mm) wide.

Antec Kuhler H2O 620 fan

The fan that comes with the Kuhler H2O 620 has an operating range of 1450 @ 26dB to 2000 RPM @ 36dB and pushes 81.3 CFM. This is a different fan from what I have seen with both the H50 and the H70 kits; those fans were in the 60CFM @ 2000 RPM range.

Installing the Kuhler H2O 620


Antec Kuhler H2O 620 mounting hardware

The Kuhler H2O 620 comes with everything needed to mount the kit into your system. There are a couple of changes from what comes with the Corsair/Asetek kits.

Antec Kuhler H2O 620 socket adaptors

Color coding, it always make things easier. The adapters that mount into the upper ring that clamps the pump to the CPU are now color coded; blue for Intel 1155/1156/1366, green for AMD and Intel 775. In the Corsair/Asetek kits in the past you had to look at the hole pattern in the adapters to figure which was which; two holes Intel 1155/1156/1366, singe hole AMD and Intel 775.

Antec Kuhler H2O 620 intel parts

First you have to pick the appropriate parts for your socket and assemble the top and bottom rings.

Antec Kuhler H2O 620 top ring

You then push the adapters into the top ring...

Antec Kuhler H2O 620 backing plate

...and the backing plate barrel nuts into the appropriate hole for the socket.

Antec Kuhler H2O 620 mounting bracket installed

Then you loosely mount the top ring and backing plate to the mother board.

Antec Kuhler H2O 620 installed

Here is where it gets interesting. Putting the kit into the system can be tricky. You have to slip the pump through the locking ring, twist it slightly to be under the locking tabs and then tighten the mounting ring, all while keeping the radiator from flopping around or falling into the case onto the motherboard. It can be done but if you have another set of hands to hold the radiator it speeds the whole process up tremendously. Once the pump is mounted and tight, then you can mount the radiator to the back of the case. If you try and mount the radiator first and then the pump, you may not be able to reach two of the mounting screws; this is very much a definite. The mounting screws are blocked if you have a second fan on the radiator. Some kits have you install the rear fan as an intake, some as an exhaust. Antec falls in with the exhaust crowd.

Legit Reviews Intel Core i7-930 Test System





Prolimatech Super Mega CPU Cooler

System specs

Here are the parts that make up the Legit Reviews Core i7-930 test system:

Intel Test Platform
Component Brand/Model Pricing
Processor Intel Core i7 930 Click Here
Motherboard Intel DX58SO Click Here
Memory Kingston DDR3 3GB 1333MHz ValueRAM Click Here
Video Card EVGA GTS450 Click Here
Hard Drive Western Digital 250gb SATA Click Here
Power Supply NZXT HALE90 750W Click Here
Chassis Cooler Master HAF 912 Click Here
Operating System Windows 7 Professional (64bit) Click Here

Test procedure

To test the coolers the system will be left idle at the desktop for 30 minutes and the temperature will be recorded. Then it will run at full load with Prime95 Blended test for 30 minutes and the temperature will be recorded. There will be 3 levels tested with our Core i7-930 clocked at a stock 2.8 GHz, a mild OC of 3.5 GHz and a high OC of 4.0 GHz. All temps will be recorded with CoreTemp, and the temp reading from all 4 cores will be averaged. The thermal paste used on all coolers will be Gelid GC Extreme.

Coolers Tested

The Temperature Testing Results


Antec Kuhler H2O 620 stock temps

At the stock 2.8GHz the Kuhler H2O 620 cooled the Intel Core i7-930 to 57.75*C, a very nice 21.75 degrees cooler than the stock Intel HSF. It is only 1 degree warmer the Corsair H70; which has a bigger radiator and dual fans. The Kuhler H2O 620 is also 2.75 degrees behind the CoolIT Eco ALC240, which has 240mm radiator, but beats the CoolIT Vantage ALC by 3 degrees. So the Kuhler H2O 620 is beating water kits with the same size radiator and hot on the heels of the kits with bigger radiators.

Antec Kuhler H2O 620 mild oc temps

After bumping the system up to 3.5GHz the Kuhler H2O 620 is still doing well. Coming in at 64*C it is in the lower 60’s, and only 3.25 degrees behind the Prolimatech Super Mega. The Kuhler is also still ahead of the CoolIT Vantage ALC by 3.75 degrees and behind the bigger radiator kits (Corsair H70 and CoolIT ECO ALC 240) by only 1.5 degrees.

Antec Kuhler H2O 620 large oc temps

Really turning the heat up, we have the system running at 4.0GHz now. The Kuhler H2O 620 comes in at 74.25*C, on par with the CoolIT ECO ALC 240 and better than the CoolIT Vantage by 2 degrees. The Corsair H70 still beat it by 2.25 degrees; again, there is a bigger radiator and dual fans on the H70.

Final Thoughts and Conclusion


Antec Kuhler H2O 620

All in one kits are becoming more and more popular as some users want the benefit of water but either don’t want to build a custom loop or have the fear they may assemble it wrong and it leaks all over their system. The self contained all in one kits like the Kuhler H2O 620 are simple to install, maintenance free, and cost much less than its custom counterpart. The Kuhler H2O 620 costs close to the same as most high-end CPU water blocks, but not much more than the middle of the road blocks.

What make these kits even more interesting is with each new generation they are getting better. The Kuhler H2O 620 is built by the folks at Asetek for Antec, and this newest generation of the cooler is giving the previous generation like the Corsair H70 a run for its money. I’m eager to see what the next evolution of these coolers will bring.

Antec Kuhler H2O 620 hose

Along with the performance uptick I really like the fact the cooling tubes were changed to the flexible rubber hoses from the corrugated tubes that kits from Corsair and CoolIT have. This made installing the cooler much easier. Those with a smaller case will also have an easier time squeezing the kit into their case due to the added flexibility.

One thing that I didn't care for too much was the fan. 36dB at full speed is getting up into to the bothersome range for me, I have heard louder, though. In the right case you may not notice it much; in a mesh case like the Cooler Master HAF-X or the Antec LanBoy Air with nothing to keep the sound in the case you will hear it. The upside is as the end user you have the ability to change the stock fan to something else. Swapping the fan out for a pair of quieter fans and changing the orientation from exhaust to intake could allow for less noise and still have nice performance. Same for even the stock fan; switching it from exhaust, as the manual says to install it, around to intake for having cool air from outside the case hit the radiator first could gain some performance as well.

Shopping for the best price for the Kuhler H2O 620 was interesting. Some places have a low price, high shipping; some are the other way round. On average you’re looking at $83.98 shipped from one of the higher rated online stores like Newegg. If you buy it direct from Antec you'll be able to get 10% off orders $50 or more due to a promotion they are doing right now. Antec will then donate 10% of the proceeds from your order to the American Red Cross to help the people affected by the earthquake and tsunami in Japan. Purchasing this cooler directly from Antec for $74.41 shipped would the least expensive method for buy one of these coolers, plus you'll be helping out the people of Japan. The Antec Kuhler H20 620 CPU cooler carries a 3 year warranty should issues with it ever arise.

Legit Bottom Line: Antec has brought a nice self-contained water kit to the table, easy to install, performs nicely, and is a lot easier on the wallet than full on custom water loop.