Antec Kuhler H2O 1250 CPU AIO Water Cooler Review

Antec and its All-In-One sealed system CPU coolers have been around for a good while now. We still have some of its first series working well here in the HardOCP offices. Today we have Antec's newly designed high end Kuhler model 1250. It has some unique offerings all based on new cold plates and big double fan radiator.


Recently, we look at Antec’s newest AIO CPU cooler offering, the Kuhler 950, and what we found was a cooler that performed decently but was plagued by other problems such as awkward installation requirements and availability. And at last check, the Kuhler 950 still is not listed on major e-tail websites. But that hasn’t deterred Antec from pushing forward and releasing an AIO designed for more serious users. The kind of users that need a higher level of cooling for their overclocked CPUs.

Today we look at the premier offering from Antec, the Kuhler 1250. The Kuhler 1250 uses a larger radiator than the 950 and employs two fans to handle the cooling duty. Antec includes the same extras as seen in the 950 which include full software control, a RGB LED embedded into the cold plate, and dual pumps which are unique to the 1250 and best of all it’s already on sale.

The big question on my mind is can Antec turn things around with the Kuhler 1250 and put the dismal showing of the Kuher 950 behind it?

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System Setup

Today's review introduces our fourth generation [H]ard platform. The test bed consists of the ASUS Z87-Deluxe motherboard, eight gigabytes of Corsair 1600 MHz DDR3 RAM and the Intel Core i7 4770K.

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Test Methods


The biggest change you will notice is the removal of hardware testing. In recent years, Intel has shifted their methods of testing to software based and so we find it acceptable to do the same.


Once again we have an integrated GPU in our processor which alleviates the need for a discrete one. With the removal of a discrete GPU comes the advantage of not having an additional variable to account for.

The iGPU will not create any anomalies in our testing as long as we practice consistent testing methods.


Corsair was kind enough to provide us with their Carbide series chassis. It provides excellent airflow and interior space and is a good reflection on current case design.

Thermal Paste

Noctua's NT-H1 thermal paste was selected as the paste of choice for a few key reasons. The thermal paste has been shown to provide excellent thermal conductivity allowing the heat sinks to better do their job. There is no observed curing time. That is, performance does not get any better over time. Any curing time could have introduced variables into the equation causing at best dubious results and at worst unreliable ones.


Ambient temperature will be kept at 25C for the duration of the tests and measured with a MicroTemp EXP non-contact infrared thermometer and cross referenced with the Sperry Digital 4 Point thermometer. Any variance greater then 0.2C will halt the testing until temperatures return within spec for fifteen minutes.


Idle temperatures will be recorded after a twenty minute period of inactivity. Any fluctuation during the last sixty seconds will reset the timer for an additional five minutes.


Load temperatures will be recorded after a twenty minute period of 100% load. To obtain this load we will be using AIDA64 Extreme Edition v3.00.2500. This places an even greater load on the CPU than before and includes some benefits. Because the load is so extreme we see the temperature vary wildly from 72C to 86C in some instances. To get an accurate reading we will utilize AIDA64’s ability to average the temperature over time. Given twenty minutes at 100% load we arrive at a temperature that accurately represents our heatsink’s performance.


Sound levels will be measured with a Reliability Direct AR824 sound meter from a distance of four feet away. With everything turned off and the room completely silent the meter registered a sound level of 38dB(A). This is a very quiet room where a simple pin drop could be heard. All sound measurements are recorded in the very late evening to further reduce any ambient noise.