Antec Kuhler H2O 1250 AIO CPU Liquid Cooler Review and Specifications

Liquid Coolers, an arrangement that keeps your CPU or GPU cool with the help of circulating liquids via tubes and powered by a pump, a cooling plate and a radiator that has fans to blow air into. Yes that's basically what a liquid cooler is but Antec took this definition to a whole new level by introducing the Antec Kuhler H2O 1250 240mm CPU Liquid Cooler. This successor of the previous H2O 1220 is not only powered by two separate water pumps, yes you read it right two separate water pumps, but also comes with a pair of non-removable fans that spin at a whooping 2400rpm all controlled by a spiffy little software running on your desktop and yes it has three color LEDs to add some bling to this big and heavy unit.
Before we progress through this review lets take a quick look at the specifications of the Kuhler H2O 1250.

Excuse me for the long spec chart but that's how its supposed to be from the official site. All in all we can conculde from the spec sheet itself that the Antec Kuhler H2O 1250 is not only big but also comes with a big bundle of wires accompanied with a lot of features.
So lets dig in further and see what else we can find out and how it fares off in the load tests.

Packing

The Kuhler H2O 1250 comes in a standard and chunky blue box with all the details and photographs imprinted. It has all the details written out in various languages so the packing is universal and area neutral. Also the box is sticking very close to the inner packing which is good as there is no space for movement and chance of breakage during transit.

Inside we find molded cardboard which is very common and provides good enough shock value to the packing. On removal I found out that the unit itself is very heavy and the cardboard casing might prove a bit too weak to support it so when you open the packaging make sure you've kept the box close to a surface underneath as chances of breakage while sliding out and removing is quite prominent.

On opening the box you find that it comes with all the installation requisites. Installation manual, GRID software CD, retention ring, back-plate, screws, rubber grommets etc. Two things worth noticing over here is that if you have an AMD processor then you don't need to use the back-plate provided along with the Kuhler 1250 as the stock plate will fit in! Second, that the retention ring and back-plate are universal for both Intel and AMD processors so installation is as swift and easy as it has ever been, just flip the back-plate for the respective processor and slide the retention ring accordingly that's all. I give full marks to Antec for this creative genius.
Pros:

Beautiful and vibrant packaging
Good enough to hold all the components in place
Universal retention ring and back-plate for Intel and AMD processors.
Installation guide is very detailed and easy to understand.

Cons:
Molded cardboard is a bit weak for this heavy unit

Closer Look

Just by looking at the Antec Kuhler 1250 you can tell that its way different from all other Closed loop liquid coolers. The radiator comes fitted with dual 120mm fans that are in turn attached to two pumps and motors each! This puts the Kuhler 1250 in a class of its own! The fans are powered by a motor that also powers a pump on top of the fan. This mechanism is followed by both fans and hence give you two water pumps that sit closely to the radiator and provides a more efficient and faster coolant flow across the radiator's area and also provides potential performance increase.
A down side of this arrangement is not only that it makes the whole unit quite thick and heavy rising many compatibility issues regarding the RAM and CPU heat sink clearance especially but also if you want to customize the radiator with fans of your own choice then it won't be possible as the pre-installed fans cannot be removed and swapped!

But their is silver lining in the cloud and its a big one! Since it comes with two pumps so in case a pump fails you will not see your CPU temperatures sky rocketing unlike all the other liquid coolers with one pump that in case of a pump fail can burn or damage your CPU for sure so I have to admit that Antec has done something really innovative and obviously functional with the Antec Kuhler H2O 1250.
At the end of the pipes is the cold plate. Once again, because the pump is not located here, the actual block is quite a bit thinner. In the middle is a translucent area with Antec's logo. This area lights up during operation, and can be used to detect the temperatures using the included Antec GRID software. This goes from a bright white to a deep red, which corresponds with cold to hot. This is a pretty neat feature, since it allows users to check their relative temperature with a quick glance. Otherwise, you might also notice there is a huge bevvy of wires coming out of the water block. One set of the wires are to power the two fans attached to the radiator. Another wire is to connect to the motherboard's 3-pin header. The last wire is used to connect to the USB pins, which allows the GRID software to control the fan speeds and detect the liquid temperatures.

On the flip side of this small puck is the cold plate. Antec has already pre-applied their own thermal paste onto the plate, so you will not have to worry about applying or buying your own paste. As for the cold plate contact material, Antec has chosen copper, which offers a thermal conductivity of 401W/mK. One last thing I should cover is the pump itself. Following the formula P = IV, the entire unit is rated at 12V, which is equivalent to 2.9W. The pumps are powered by the motherboard's 3-pin header so its a safe wattage to withdraw.

The GRID software included with the Antec Kuhler H2O 1250 can be used to alter the LED colors produced from the water block, or you can make it temperature dependent. There are also three profiles for fan speeds: Extreme, Silent and Custom. Extreme sets the fans at around 2200 RPM and increases upwards from there, depending on the load. Silent sets the fans closer to 600 RPM, and again, increases depending on load. Custom allows users to adjust the fan speed to their liking. The software is simple and easy to use, and I never had any issues running GRID.

The overall build quality is solid; the radiator is, well, a radiator, the pumps are stable and silent (they lack the annoying whirr that other pumps exhibit), and the fans don't cause any rattling or vibration within the case. The copper three color LED coldplate is from a common supply and uses standard design, but is high-quality nonetheless.
Pros:

Dual pumps means better liquid flow and safeguard from pump failure
Thin copper cold plate
Temperature dependent cuatomizable LED
GRID software is a handy tool and easy to install
Innovative design

Cons:

Radiator is too thick and bulky for most of the cases
Fans cannot be removed or swapped

Load test

Installing the Antec Kuhler H2O 1250 was one of the easiest installation I've ever come across so far courtesy to the universal mounting brackets but yes the wires were a bit tough to handle, not big deal though. The radiator and fans just managed to keep clear from the CPU heatsink on the Gigabyte Z87X D3H and RAM clearance was fine enough for my Kingston HyperX fury mainly because they don't have an elevated heat spreader.
I tested the Kuhler 1250 on the following configuration:
CPU: Intel Core i5-4670K (Stock settings and OC to 4.3Ghz)
Motherboard: Gigabyte Z87X-D3H
RAM: Kingston HyperX Fury 16GB
Graphics: EVGA GeForce GTX 760 2GB
Chassis: Antec GX900 (Courtesy Antec India)
Power: Antec VP500PC 500W (Courtesy Antec India)

To stress the CPU we used Prime95 for half and hour along with Unigine Heaven 4 as the Antec Kuhler H2O 1250 draws air from inside the case so GPU heat was necessary to emulate real life conditions. Also I removed the pre-installed top 2x120mm fans provided along with the Antec GX900 and put one in the back as exhaust and other at the bottom as intake for cool air.
The following results were obtained on stock frequency

And at OC 4.3Ghz the results we observed were

As we can see that not only the Antec Kuhler H2O 1250 passed with impressive stats but also it beats down the competition by quite a significant difference. Even at a silent mode with fans spinning at just 600 rpm the H20 1250 performs aswell as the Corsair H100i and Corsair 110 that spin at full speed.
All in all I'd say that Antec has finally hit the nail on the head at the price of noise as the unit produced 34dB at Silent and 48dB on Extreme mode which is a bit too much for many people. But at this performance I don't mind some noise around me.

My Verdict

If nothing else, typing Kühler has helped me memorize the ever-important alt-0252 code.

Just kidding, the Antec Kuhler H2O 1250 has not only proved that there are many ways to re-design and improve the performance of a saturated AIO liquid cooler field but also at just $90 retail price proved that true performance is not always for the riches. The dual pump system and the bulky radiator block distinguishes the Kuhler 1250 from any other liquid cooler present in the market today. A little compatibility & noise issues are there but the provision of a universal backplate and retention ring along with the GRID software and LED illuminated coldplate sweetens up the deal.

So if you hate complex installation methods or simply want true performance in terms of temperatures along with distinguishing looks at a reasonable price tag then the Antec Kuhler H2O 1250 is and should be your pick.
Truly a unique product and enthusiast oriented CPU cooler, another job well done from Antec!
I give it a respectful 9.5/10

Thursday, 2 July 2015