Antec KÜHLER H₂O 1250 – Test and Review

Antec’s KÜHLER H₂O AIO liquid CPU coolers are comprised of three different models:

  • Antec KÜHLER H₂O 650 – high-performance liquid cooling featuring a single slot slim radiator cooled by one 120mm fan PWM powered and regulated. The water flow is guaranteed by a single water pump.
  • Antec KÜHLER H₂O 950 – high-performance liquid cooling featuring a single slot thick radiator cooled by two 120mm fans PWM powered and regulated. The water flow is guaranteed by a single water pump.
  • Antec KÜHLER H₂O 1250 – high-performance liquid cooling featuring a double slot slim radiator cooled by two 120mm fan PWM powered and regulated. The water flow is guaranteed by two water pumps.

At DVTests we have already reviewed and tested KÜHLER 650 (check out the thorough test and review) and now it is time to do the same operation for KÜHLER H₂O 1250. For today’s test and review I have received the last in the list, hopefully not the last in performance – KÜHLER H₂O 1250. The model arrived in a medium sized carton box (one you should expect if purchasing a 240mm water cooling radiator) with black/blue layout theme, all around nicely colored and readable information was available throughout the entire box. On the front as usual you are presented with a big picture of the product inside and Antec has put some marketing after effects on the cooler. KÜHLER H₂O 1250 is “frozen”, speaking probably of its cooling capabilities and what it should do best.


A blue stripe goes round the box with the product name, as well as technical information around its sides. All I can say if you find the box on a shelf in a store you just might be able to know what you are purchasing. Let’s say you purchased the product and first thing to do is to unpack it: Visible right from the start is a small, folded installation guide on top of soft styrofoam piece, covering the cooler below. The installation guide seems informative and intuitive, with handy pictures and information regarding the installation of the large cooler. After removing both the installation guide and styrofoam I finally saw some pieces of hardware, carefully packed in nylon bags.

Every piece had a specific slot in a recycled paper box and looked well protected overall.

Antec KÜHLER H₂O 1250 – back side of the box Antec KÜHLER H₂O 1250 – packaging
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There was no visible damage to the assembly, so I proceeded with the unpacking activity.

Before moving on with what’s in the package story, let’s appreciate the visual appeal of Antec KÜHLER H₂O 1250 for a moment.


As you can see, the whole AIO is comprised of two fans, a lot of cables and a slim design CPU contact plate, due to the integration of the pumps above the fans. And as you read “pumps” you might be asking yourself a question, yes, there are two water pumps working side by side to deliver even greater performance and redundancy.



As I’ve said earlier, inside the box of this water cooling solution there were individual openings for both the cooler and the other included goods – by that I mean the additional accessories enabling you to install KÜHLER H₂O 1250 on both Intel and AMD platforms. The mounting mechanism supports the following sockets:

  • INTEL COMPATIBILITY – LGA 775/1150/1155/1156/1366/2011


These are the additional package contents of KÜHLER H₂O 1250:

  • plastic mounting bracket
  • metal alignment ring
  • additional brackets for improved radiator compatibility
  • CD with Antec Grid software
  • a bag with 4 x soft foam adhesive dampers
  • a bag with 4 x hollow screws
  • a bag with 4 x Intel compatible bolts with springs
  • a bag with 4 x Intel socket 2011 bolts with springs
  • a bag with 4 x AMD compatible bolts
  • a bag with 8 x additional screws for push/pull configuration
  • a bag with 4 x small screws for radiator attachment
  • a bag with 4 x rubber spacers

I should say that Antec did an outstanding job with the quality control as all the included accessories are quite solid in terms of build quality and don’t feel flimsy, even though the motherboard bracket is made of plastic material. Another added bonus is the overall black finish to the screws and bolts for optimal visuals when the cooler is mounted over the CPU.



KÜHLER H₂O 1250 is made to cool the liquid via a 240mm aluminium radiator with moderate density of the fin structure. The radiator has dimensions of 280mm x 120mm x 27mm and the assembly looks immensely large due to the water pumps integration on top of the fans, so you do need to consider a large case to avoid conflicts with other parts, such as motherboard or RAM modules. If you are using a test bench style case, there is no need to worry.


All of the radiator fins looked intact and evenly spread, overall build quality is good and I have to say I am pleased with the finishing paint. On the back (or top) of the radiator there are eight more screw openings if you want to consider a push/pull configuration. According to Antec the radiator is filled with safe, environmentally friendly, anti-corrosive liquid, but there’s no way to check that, so we just might want to give thumbs up to Antec for caring for the planet.


The tubing is attached firmly to the one end of the radiator and is made of flexible rubber that is 300mm in length and is also rather thick. Where the tubing makes connection with the radiator, there is additional strengthening rubber with adhesive material, so basically common weak spots feature some good support.

Let’s move on to the water pumps installed in this AIO… KÜHLER H₂O 1250 is featuring two ceramic bearing water pumps that have 50.000 hours of MTBF at 3000 RPM maximum. For power connection they use a 3-pin connector and 12 volts is the maximum operating voltage. The time is right to say that if one of the pumps fails the cooler should be able to provide enough performance even with one working impeller. I believe I’ve covered the pumps and radiator, so the time has come to check what fans are used in order to cool this large radiator.



Being a 240mm pre-filled radiator, KÜHLER H₂O 1250 needs two fans in order to operate properly, thus two fans are included and directly mounted on the radiator. Some users may find that awkward or not user friendly, because you are unable to change them.

Antec KÜHLER H₂O 1250 – cooling fans Antec KÜHLER H₂O 1250 – fan directional blades
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The included fans are 120mm x 120mm x 25mm and are PWM controlled, according to the CPU temperature. They feature liquid state bearing and are rated at 50.000 hours MTBF, same as the water pumps. The two fans are able to provide airflow level range from 25 to 98 CFM at respectively 600-2400 RPM. At these RPM levels you should expect static pressure level of 0.3 – 4.8 cubic mm water weight. On the back of each fan there is only the Antec logo, with no additional information.


Basically the fans are the only thing you can disassemble from this cooler with removing eight long screws and pulling them out under the water pump assemblies. Both fans look quality made and the plastic used for the propeller is very hard and solid, and bending the fan frames was not an easy task.

Next step in this review is to prepare the cooler for installation and this could be performed with the help of the user manual, as well as the included mounting bracket and screws.

Test motherboard Necessary parts for installation
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The cooler will be installed on an Intel socket 1150, thus I will be using the included parts for Intel installation and the parts are:

  • plastic mounting bracket
  • metal alignment ring
  • 4x small hollow screws
  • 2x soft foam adhesive dampers
  • 4x rubber spacers
  • 4x Intel compatible bolts with springs


Firstly, the foam adhesive dampers need to be placed on the right side of the plastic backplate in order to be later on attached to the motherboard socket plate and the hollow screws go into the corresponding socket marks (each socket is labeled). Secondly, on the metal ring there are marked locations for Intel and AMD compatibility that need to be fixed with the included rubber spacers. Once you align the correct manufacturer (in this case Intel) you place the rubber part in a small channel and by doing that there is no way for movement.

Backplate attached CPU awaiting installation of water block
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After aligning everything and putting it where it needs to be, the plastic backplate was ready to be glued to the motherboard. It is a simple operation and it ensures that the plastic backplate stays in place for easier installation of the contact plate. As you can see from the right photo, the hollow screws are sticking out just a little and are ready to take the longer screws with springs.

Next thing was to attach the metal ring onto the contact plate and this is done by aligning the ring with the channels onto the contact plate and then using a twist motion to lock it into place.



For this particular AIO liquid cooler that is the most essential part, because all the necessary cables are attached to the slim contact plate, it is the brain of KÜHLER H₂O 1250. Supplied cables attached to the base plate are the dual fan connectors (PWM) for the 120mm fans, as well as two additional fan connectors if you plan to upgrade the setup with two more 120mm fans in the future. For the pump a 3-pin connector is used and for the software control you have to plug a long cable into the USB 2.0 port at the bottom of the motherboard. Every single cable has a label on it so there is no way of mixing things up.



That covers the attached cables, let’s talk about the contact plate. It is made of pure copper and as you can see from the photo it is surrounded by screw heads, a lot of them. Their job is to keep the plate firmly attached to the plastic base and to ensure perfect contact at all times. Antec was kind enough to supply the unit with pre-applied thermal compound in order to relieve you from the obligation to put thermal paste yourself. I am not aware of the quality that this thermal solution offers, but in the test section I guess we would find out if it does the job.

Okay, now the cooler is ready to be mounted on the motherboard and later on put to the test.



Now that the cooler is mounted, I believe it is time to install the included Antec software (Antec GRID) and proceed with the testing methodology.

  • CPU: Intel i5-4670K
  1. At standard frequency 3.4 MHz (at 1.02V, set to Auto when not OC-ing)
  2. At low overclock frequency of 3.9 MHz  (at 1.24V)
  3. At medium overclock frequency of 4.3 MHz (at 1.25V)
  • Motherboard: AsRock Fatal1ty Killer Z87
  • Video card: MSI AMD R9 280X GAMING 3G
  • Memory: A-Data XPG 8 GB Dual channel, 1600 MHz
  • Solid State Drive: Intel 530 Series, 120 GB
  • Hard drive: Western Digital 640 GB Black Series
  • Case: Antec Nineteen Hundred
  • Power supply:  Corsair RM750 W, Fully Modular
  • Thermal paste: supplied from Antec

For the test I will be using the supplied two 120mm fans and using the Antec GRID software I shall see how the cooler performs in both Silent and Extreme mode.

The tests were conducted in a closed system with:

  • Three Antec 120mm fans, installed as intake, rotating at 1200 RPM
  • Two Antec 120mm fans, installed on the HDD cage inside the case, rotating at 1200 RPM
  • One Antec 120mm fan, installed as exhaust at the rear of the case, rotating at 1200 RPM

Room temperature of about 22 degrees.

And here I want to describe my testing method.

I will install Antec KÜHLER H₂O 1250 and do stress tests using Prime95 AVX software with constant load on the cooler for 14:30 minutes with custom settings of minimum FFT size (in K of 128), max FFT size (in K of 128) and Run FFTs in place at standard frequency of 3.4 GHz (at 1.029V), at low overclock frequency of 3.9 GHz (at 1.249V) and at medium overclock frequency of 4.3 GHz (at 1.254V) using the supplied fans installed on the radiator.

And this is what the CPU cooler looks like when installed inside the case and ready for testing.

AIO Water cooler installed View through the acrylic window
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Now let’s check out the test results after the intensive stress testing:

Antec KÜHLER H₂O 1250 @ 3.4 GHz – SILENT Antec KÜHLER H₂O 1250 @ 3.4 GHz – EXTREME
Antec 1250 @3.4 SILENT Antec 1250 @3.4 EXTREME
Antec KÜHLER H₂O 1250 @ 3.9 GHz – SILENT Antec KÜHLER H₂O 1250 @ 3.9 GHz – EXTREME
Antec 1250 @3.9 SILENT Antec 1250 @3.9 EXTREME
Antec KÜHLER H₂O 1250 @ 4.3 GHz – SILENT Antec KÜHLER H₂O 1250 @ 4.3 GHz – EXTREME
Antec 1250 @4.3 SILENT Antec 1250 @4.3 EXTREME


All of the results above have been summarized in the following charts:

Antec kuhler 1250 - temps

And the fan speed during the tests:

 Antec kuhler 1250 - fan speed

I believe the time for conclusions has arrived.



1. Antec KÜHLER H₂O 1250 performance:

The results speak for themselves, really. Now, I have to be honest and by that I can say that the performance of this cooler impressed me, no doubt about that. Starting with the overall build quality that it offers right to the solid, concrete stable cooling capabilities this monster of a AIO water cooler brings to the table. Also the software offers great customization options for the speed of the fans and performance to noise ratio. The CPU used in the tests is rather hot, especially when some voltage is applied, but as seen from the result charts the temperatures are not even close to critical and there is more room to work with, too. If my chip was better probably even 4.6 – 4.7 GHz would have been achievable, while maintaining reasonable temperature levels.

Mounting kit is fairly straightforward to install, as always you have to follow the steps if you don’t know what you are doing. There are a couple of things that require attention such as the rubber stoppers on the metal bracket and the alignment openings for each of the CPU sockets. Bolts are equipped with springs and when tightened enough they just stop to prevent braking the socket bed, which is very thoughtful of Antec to do.

Silent mode is absolutely great as it manages to keep the CPU cool enough even when extreme stress is applied on it, given the fact that this stress test is too far away from anything that normal day-to-day usage of the CPU can bring. Initially the noise levels in Silent mode are absolutely tolerable and the cooler is almost dead silent, indeed. The fans are barely audible at low RPM levels and you can hear them somewhere around the 1000 RPM mark, although the noise is not near to intolerable, only slight humming sounds coming from the case.

Extreme mode is, on the other hand, absolutely hellish in terms of noise level, but the performance you get is absolutely worth it and I mean every single dBA added is a degree Celsius lower. Solid, extreme performance, mainly for highly overclocked and working in stress environment CPU’s that actually demand the cooling capabilities of the cooler. Noise is greatly increased and I wouldn’t imagine anyone deliberately using it when watching a movie or playing intensively gaming sessions – it’s an overkill. Extreme mode is created for breaking the GHz barriers with hot processors.

2. Antec KÜHLER H₂O 1250 appearance:

Although a bit bulky, the cooler is simply beautiful with a pretty much standard color scheme that always works flawlessly – black and white. I believe it is liked by the majority of users out there and this is perfectly fine as there is nothing to complain about the looks of the cooler. Now add one more point to the colored LED on the contact plate that you can customize via the Antec GRID software and make it more attractive to your liking. Very distinctive feature of this cooler are the water pumps located on top of the dual fans, it just separates Kuhler 1250 from the other 240mm water cooling AIO coolers a bit more.

Truly a unique product and enthusiast oriented CPU cooler, another job well done from Antec!

According to my review, I think that Antec KÜHLER H₂O 1250 deserves the following reward:


Official price (MSRP) for Antec KÜHLER H₂O 1250: 119 USD

Official warranty: 36 months

I thank Antec for the test sample.


Antec KÜHLER H₂O 1250 – Test and Review
Excellent water cooler, although compatibility with smaller cases might be compromised. Very good cooling in Silent mode, even for intensive CPU operations.
8.8 Total Score
DVTests recommends this product to users with high demands for cooling and high tolerance for noise.

Excellent water cooler, although compatibility with smaller cases might be compromised. Very good cooling in Silent mode, even for intensive CPU operations.

Noise Level
Additional accessories
User Rating: 4.45 (1 votes)

Nikola Milanov is reviewer and newsman at DVTests and has more than 6 years of experience in telecommunications. I'm really enthusiastic about the website and its development by sharing a user's point of view and experience with the products we test. We are honest and objective in all of the articles, the products get tested and reviewed thoroughly with no exception! Feel free to ask any questions in the comment section or use the emails in About us page!
  1. Reply Xilob 12.05.2016 at 22:31

    How to remove fans from a radiator? I mean what screwdriver is used to to that? Thanks in advance for an answer.

    • Reply Nikola Milanov 16.05.2016 at 14:01

      Hi XILOB,

      Just a normal Philips head screwdriver will do the work 🙂


  2. Reply Vishvesh Mishra 30.06.2015 at 16:43

    Nice review, just wanted to know if this cooler will fit in the Antec GX900 Mid-Tower cabinet?
    The top has provision for 240mm rad but the shear thickness of this radiator block on this one with the fans and pumps make me doubt over it?

    • Reply Nikola Milanov 30.06.2015 at 17:03

      Thanks for the kind words. Honestly I have to say that the fit is dependent on the RAM modules you will install as well as if there is a higher heat sink on the motherboard. I have not tried that case, so I am not familiar with its internal layout in particular. I believe it should fit tightly, but can’t say 100% that I am positive. And yes, you are right about the thickness of the rad, along with the protruding pumps.

      P.S: I would try it.

      Best regards,

  3. Reply Dk_vr 29.09.2014 at 16:09

    Thank you for the good words but here I should point that I am not the author of this review.
    Anyway nobody cares for silence in fact the cooler provide outstanding cooling performance.

  4. Reply Nikola Milanov 29.09.2014 at 14:49

    Sadly for us, the silence loving users, this piece for cooling isn’t anywhere near silent when the fans spin up above 1000-1200 RPM. Good thing, however, is that it offers plenty of cooling potential even when fans are rotating at 600 RPM. Therefore you have one silent cooler with superb performance. 🙂

    Thanks for the comments guys!

  5. Reply Dimcho 29.09.2014 at 13:42

    Performance and accessories are very good, but the noise level is just a little bit disturbing for quiet-loving person like me.

    Great review, Dobri 🙂

  6. Reply PepiX 29.09.2014 at 13:35

    Not cheap.. but not that expensive for what it offers I guess.. It is a shame one can’t get the extreme performance with total silence (at least not in the mainstream cooling :D). Good review DK 🙂

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