Antec Kuhler H2O 1250 AIO CPU Cooler Review

Antec takes a whole new approach to what they think an AIO should be. You have to see what the Kuhler H2O 1250 is all about.

Published Wed, Jan 8 2014 9:04 PM CST   |   Updated Tue, Nov 3 2020 7:00 PM CST
Rating: 75%Manufacturer: Antec


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Let us imagine for a moment that we could do anything we wanted with the components that make up an AIO, just for the sake of giggles. With all of the basic offerings out there, if you are looking to stand out in the crowd, you are going to have to do some pretty drastic engineering here. So, let's say we grab a dual 120mm radiator to use as our heat transfer device. But, why not try and improve on the basic AIO concept as well, and go with dual pumps? Of course we can't stack them on the head unit now can we?

So, we have to devise a way around this. Removing the pump from the head unit is a good idea, and would result in an even flatter head unit that would be the lowest profile head unit on the market. Without a pump in the head unit, and the fact that we are going with two of them, it leaves little other than the radiator as where to mount them, but how would we do this and still not affect the fan placement on one side, or completely block off airflow if we did block fan placement?

Antec has come out with this exact concept, and while it is a bit strange and unusual to look at, it is one of a kind, and unlike anything I have seen before. In fact, with a bit of creative plumbing, a dual single pass radiator, two fans, and two pumps, Antec is offering one of the thickest AIO kits to hit the shelves. The stacking of devices was their solution, and on a standard 27mm thick radiator, there is 25mm of fan and frame. There is also a pump housing that is similar in size to the fans hubs, as not to block incoming airflow. In this instance, an image is worth a thousand words, because you really need to set your eyes on this AIO to get the full effect.

This new creation is referred to as the Kuhler H2O 1250, keeping it in the family of the Kuhler H20 series that Antec is already known for, and is truly unique amongst other AIO offerings out there. Stick with us as we put the 1250 through our gantlet, and see just how well this design copes with the copious amounts of heat that our test system provides us.

Specifications, Availability and Pricing

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Let's try to follow the list a bit, and then we will do our best to explain how this setup will work. Antec mentions the copper cold plate first, and then gets right into the pump's specifications. The impeller is suspended with a ceramic bearing that will offer 50,000 hours of run time at a maximum of 3000RPMs. The radiator is of course aluminum, and is 159mm long, 120mm wide, and 27mm thick. The tubing is 300mm in length and made of black rubber. There is thermal compound pre-applied to the block, and this cooler will fit on all the latest sockets from both AMD and Intel. The fans used to cool the radiator are 120mm, on liquid state bearings. These also have a 50,000 hour lifespan, and they turn at 2400RPM. These fans can also deliver 98CFM of flow, offer 2.78mmH20 of static pressure, are rated to 38dB, and use a 4-pin connection. There is also 700mm of USB cable for the software, and the Kuhler H2O 1250 is backed by a three-year warranty.

How this all works is pretty simple. Let's start at the head unit and travel out the tube to the radiator. There we are picked up by a pump, and then pushed into the radiator, run along one long half of the radiator. At that point, you come back out of the radiator, down through the other long side of the radiator, and are then sent down the other tube, and back to the head unit. The main issue I see right out of the gate is that what used to be only four leak points from the tubing has now become a total of ten points, in what are now five sections of tubing. It should also be considered that with this cooler, due to the frames being custom, the fans applied cannot easily be replaced, and cleaning may become an issue as well.

The Antec Kuhler H2O 1250s are already on the shelf, but pay attention when you are looking to buy it. The MSRP was set on these at $109.99 US dollars. What I found is both good and bad when looking to buy this cooler. The Newegg listing at first lists the device at $119.99, but they are currently running a $30 mail in rebate offer, which brings the pricing to $89.99. Of course, if you tend to shop at Amazon, be prepared. For some reason they have the 1250 listed for over $200. I would suggest passing on that deal.

Considering we can get this dual pump, dual radiator AIO for the cost of most single radiator and single pump solutions, I am intrigued, to say the least.


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Above a seriously frozen rendering of the Kuhler H2O 1250, there is the line that states this is the "next generation, maximum performance, liquid CPU cooling solution." There are also five icons across the bottom to denote key features.

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The end of the box offers a chart of this cooler tested against stock cooling, another maker's AIO, and various versions of the Kuhler products on an i7-3960K. The bottom section offers a list of things contained in the packaging.

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The back carries on more of that bright blue to attract your attention. Here it attracts your attention to things like the copper plate, dual pumps, two fans, RGB LED control of the Antec logo on the head unit, and the GRID software.

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At this smaller end of the packaging, Antec provides potential buyers with a specifications chart that covers all of the major questions like dimensions, and fan capabilities.

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One last panel to cover, and then we can open the box. Here, we are given the socket compatibility list. At the right they cover the AQ03 three-year warranty, where to go for support, and where this was designed and built.

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Inside of the box, under a layer of foam which has been removed, the radiator and most of the tubing have been bagged up. The head unit and the hardware are currently under the installation guide, which is also found under the foam. With everything being as compartmentalized as it is, the Kuhler H2O 1250 arrived in perfect condition.

Antec Kuhler H2O 1250 CPU Cooler

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I know this image looks like an AIO with a bit of spaghetti attached to it, but I thought an image of the full kit up front was mandatory in order to understand what we explain as we continue with the review.

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The head unit is very thin, about two-thirds to half of the height of the standard offering. The outside offers a textured finish that surrounds an illuminated center cap with the Antec name on it.

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At the top of the head unit, both of the plastic swivel fittings that take the coolant in and out of the block are placed closely together. Somehow, we even got one put together with an extra bit of thermal paste here too.

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The left side of the head unit has a groove cut into it that allows all of the wiring to come out, and be connected to all the appropriate devices.

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In that set of wires, you get the USB 2.0 connection for software control, two fan leads that offer the 4-pin connections to power fans (for a total of four), and the 3-pin fan connector to power the head unit's LEDs.

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There is the standard plastic cap on the base when you receive it. However, I think something drug on the base well before that, as there is a mark in the TIM application, and is likely where the paste on the side came from. The plastic cover was clean, and showed no signs of contact with this TIM.

Antec Kuhler H2O 1250 Continued

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After wiping all of the paste off, we found a base that has semi-circular milling marks in it still. Once a blade was held against it, the convex shape of the cold plate became very apparent.

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After pulling out the tape measure, we found that the tubing on this cooler from clamp to clamp is ten inches in length. While this may save a few pennies in production costs, with all the tubing used elsewhere, I would have liked to see a couple more inches added in here.

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As the tubing reaches the radiator, it takes a trip into the first of two pumps. Once spun through the pump, the coolant is sent into the bottom right side of the radiator. Also, notice that all of the fittings are glued, in an attempt to eliminate those leak points.

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Once the coolant reaches the top of the radiator, it comes out of the radiator on the right side, and is passed through the second pump. This time, the coolant is then sent once more through the left side of the radiator, and is then sent back to the head unit from the bottom, as seen in the previous image.

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Looking at the radiator from the back, you can see the chassis mounting for adding extra fans is all ready to go, and you can also see the high FPI density used in these aluminum radiators.

Accessories and Documentation

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Along with the Installation guide, you are also given a CD with the GRID software on it. Don't worry if the disc is scratched or gets damaged, the software can be found on the Antec site as well.

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The cooler comes with a universal back plate that is made of plastic, and will not short out against the motherboard. The top mounting ring is a bit different than most though. This ring can be used for both AMD and Intel mounting, just by adjusting the four legs, and adding rubber spacers to keep them in place.

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Since this solution is so thick from top to bottom when hung in a chassis, Antec has provided offset mounting brackets to add room between the radiator, and the memory and PWM areas. You also get a pack with four pads for the back plate, and the rubber spacers needed to lock the top mounting ring's legs.

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There are also three sets of screws for the head unit. Antec sends a kit for AMD, a set for the majority of the Intel sockets, and a set specific to LGA2011. You are also given eight short screws to mount the radiator into a case, and there are four inserts that go into the back plate.

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For some additional testing, Antec also sent this second pair of 120mm fans, and the screws needed to install them onto the radiator. So, in the charts, we will have the testing in the stock configuration, as well as a push/pull setup with all four fans running.

Installation and Finished Product and Software

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As part of the initial setup, you need to take the legs and adjust them to the correct socket. Here, we need to slide it from the left AMD location, and move it right. Once that is done, you insert the rubber into the groove to keep the leg from moving back.

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For our test system, we will be using the 115X mounting holes. You install the inserts by forcing them to snap into the back plate. This requires the use of something to press the insert, like pliers, or a screwdriver.

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After getting the inserts into the plate, the last thing you will need to do is to apply the foam padding down both sides of the plate. The 3M covering is then peeled off to allow this plate to stick to the back of the motherboard.

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With AMD, either end up is fine, but with Intel you need to be sure to get the plate on correctly or the socket mounting screws will make the plate sit funny, and disrupt the mounting process.

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After taking the metal ring and guiding it through the grooves on the side of the head unit, it then twists to lock into the head unit. At that point, you can go about sending the thumbscrews down to mount the head unit to the motherboard.

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The USB 2.0 cable is sleeved black to help hide it, but there is plenty of length to run it behind the motherboard tray, and still make it to the bottom of the motherboard for connectivity.

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This is how we chose to mount the Kuhler H20 1250 for testing. Actually, with the limited amount of tubing, and the chassis being so large, there weren't too many options as to where we could hang the radiator without too much strain on the shorter tubing.

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The GRID Software has failed for me, and it's not the first time I have had issues with Antec software. With a fresh Windows 8 installation, installing the software did launch the app, but the RPMs were at 9999 before it dropped to all zeros, and the -29 degree temperature isn't very accurate. What sucks is that due to this, the fan controls, LED controls, and the settings are non-functional.

The Test System and Thermal Results


I would first like to thank ASUS, InWin, Corsair and Fractal Design for supplying products for me to test with. To see our testing methodology, and to find out what goes into making our charts, please refer to our CPU Cooler Testing and Methodology article for that information.

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One thing to consider here, is that when you limit the voltage to the fans, you are also limiting the RPM of the pumps. Even so, with only 7.5V supplied through the fan leads, the average temperature was 50.25 degrees. We made a run with all four of the fans on the radiator as well, but here, that was only worth a quarter of a degree advantage. The idle temperature at this stage was a mere 27.5 degrees with the fans spinning at 1300 RPM.

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Once we let the fans and pumps loose to do their thing, we did see some pretty good performance out of the Antec AIO. As it shipped to our lab, we got an average result of 69.83 degrees, putting the Antec in fourth place overall. Adding the second pair of fans is an added cost, and for that investment you are offered just over a degree of improvement. The stock fans were spinning at 1400 RPM at this point, and the optional fans in the four fan configuration were at 2200RPM.

Noise Level Results

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For the stock settings, we were limiting both the pumps and the fans speeds, and doing so leaves the 1250 near silent, with a 33 dB reading at this point. Inside of a chassis, you would never hear this, but give it the chance, and the Kuhler H2O 1250 will scream like a scared teenage girl.

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With the fans and pumps now set for maximum velocity, there is a droning sound that is hard to shake and get out of your head. The 65 dB reading here seems like it would be loud for sure, but there is also a pulsation to that noise that could almost put you in a trance. To be honest, with all the runs we do at the overclocked level of testing, the end of the testing could not come soon enough. This is just too loud to be even remotely enjoyable to use at this level.

Final Thoughts

The thermal performance was pretty good, and this is definitely a unique take on an AIO. The real issue is that we see tons of AIO offerings, and we have seen it doesn't have to be the loudest to win; it doesn't need to put you into a trance to make you think it is the best. The software failed, so LED use and settings became unusable during testing, and with all the glue oozing from the tubing, I wasn't very impressed. I have to give them credit for originality and ingenuity, but this is one product that definitely looked better on paper than what it delivers in real life. It is almost like we took a step backwards with the huge size of things, but at least they offered some offset brackets to try to alleviate any issues that this super thick radiator, fan, and pump design has.

It is really hard for me to take on a product that does so well in the thermal charts, and doesn't make your ears bleed. But, when this is on full speed, watch out, it may just make you want to either plug your ears with more than a headset, or simply never run the cooler that high, and that lessens its efficiency, and brings down the level of useable performance. Not to mention the real pain in the rear end that cleaning and maintaining the flow of the fans and radiator has become in this design. Even if you remove the fan screws, the pumps are still connected to the radiator with very short tubing, and getting the fans out of the way is near impossible.

Aside from the better than average results this offers, I would have to say the mounting hardware is the best part of this kit. If you don't believe me, and think there isn't a fan or setup on the planet that your ears can't handle, by all means try your luck with the Antec Kuhler H2O 1250. And, I strongly suggest you go the Newegg route to save a bunch of money. Had the fans and pumps not been such an irritation at full speeds, the $109.99 MSRP would be an awesome price, and with the $30 MIR offered at Newegg to bring their pricing to just under $90, it may be worth a try just to say you did.

The thing is, the way this is designed, to get the most out of it you have to deal with the annoyance of these fans, and the potential vibrations and pulsations this setup will deliver into a chassis as well. If I were in the market for a dual 120mm AIO, I would personally keep on looking.

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Chad joined the TweakTown team in 2009 and has since reviewed 100s of new techy items. After a year of gaming, Chad caught the OC bug. With overclocking comes the need for better cooling, and Chad has had many air and water setups. With a few years of abusing computer parts, he decided to take his chances and try to get a review job. As an avid overclocker, Chad is always looking for the next leg up in RAM, cooling, as well as peripherals.

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