Antec Kuhler H20 1250 CPU Cooler Review

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With competition in the sealed All In One market at an all-time high, even firmly entrenched companies like Antec are starting to feel the heat. Consumers now demand more and the days of small improvements to water blocks being enough to justify an entirely new model (and price tag) are gone. Unlike when the original Kuhler was released, consumers now have more options than ever and with Cooler Master, NZXT and even SilverStone offering unique designs, Antec needed to do something different. The all-new $119 Kuhler 1250 is just that; it represents a radical departure from the competition

In comparison to its immediate competition Antec has offered an enticing feature set which are unique to the new redesigned Kuhler line. On paper, these differences aren’t readily apparent since just like tits competitors the Kuhler 1250 consists of a 240x120mm radiator, advanced water block, two stock fans, advanced tubing and an integrated water pump. However even just a quick glance shows that Antec has combined these components in an entirely new way. Instead of opting for the typical combination water block and pump, Antec has taken a cue from CoolIT’s early designs and moved the pump off the water block.

Unlike previous designs, which used a single standalone pump, Antec has combined the fan motor and water pump motor into a single unit. This allows the Kuhler series to effortlessly scale up pump performance along with radiator cooling abilities. As water cooling enthusiasts know all too well: the faster the water can move over the water block and through the radiator the more effective the loop can be at cooling the CPU.

Even with these new features Antec has kept things competitive and the Kuhler 1250’s online asking price of $119 is quite comparable to Corsair, SilverStone and a host of other companies who offer dual bay designs. Add in improved GRID software for controlling noise and temperatures and Antec may have found a way to ensure their Kuhler line stays relevant and on top of the changing marketplace.

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Closer look at the Kuhler 1250

Closer look at the Kuhler 1250

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Like any CPU cooling device the Antec Kuhler 1250’s shipping container is both aesthetically pleasing and informative. The front of the box consists mainly of a large color photo of the 1250, with the back and sides covered in graphics and text which will allow any consumer to make an informed decision before purchasing it.

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The internal protection scheme is classic Asetek and much like any Asetek ODM’ed unit consists of a sturdy cardboard container and foam topper.

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Antec hasn’t held back with the accessories which are comprehensive and consist of high quality components. These include everything needed to install the Kuhler 1250 onto any modern Intel or AMD socketed system, including older Intel socket 775 systems. They also happen to reflect Asetek’s latest design enhancements which make them quite different.

The plastic AMD and Intel back plates have been replaced with a single all-in-one design, the captured retention bolts are now free standing and use springs for tension. Even the top ring itself has been redesigned and enhanced compared to previous Asetek models.

In total there is an installation pamphlet, mounting hardware for all current Intel and AMD systems, an all in one plastic backplate which is designed to work with both Intel and AMD systems, and two adapter brackets. The last item is unusual since it allows the Kuhler 1250 to be installed slightly offset from the case’s exhaust ports. For most cases these brackets will not be needed, but due to the rather deep nature of this cooler, they may be needed so that motherboard heatsinks do not interfere with the Kuhler 1250’s fans.

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Even on just a cursory glance the Antec Kuhler 1250 doesn’t look like the typical All in One sealed water cooling device. It may consist of the same four key components but the waterbuck appears to be too thin, the combination fan and radiator is too thick, there are way too many pieces of tubing connecting the parts together and everything just looks different. In practical terms this is because the new Kuhler 1250 is entirely different than any other AIO on the market today.

While Asetek does manufacture this unit, it is a ground-up Antec design so they didn’t just pick an off the shelf unit like others. There are still usual components but they are arranged in a unique way to optimize several cooling features built into the Kuhler.

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While there are numerous differences between the typical OEM Asetek model and this new Kuhler 1250, they all stem from one key design aspect: pump location. Typically these units incorporate the pump atop the CPU water block in order to increase flow rates and overall efficiency but not this time around. Rather, Antec has designed it so the waterblock simply incorporates a color LED, fan controller and some USB circuitry while the pump is located atop the water block’s fans.

Combining the fan and pump motor into one unit has given Antec the luxury of easily increasing pump performance without boosting noise levels. Usually to increase flow rates in a typical AIO design, a louder single pump is used whereas with this new Kuhler, Antec can simply used more pumps. The end result is the same – increased water flow and water pressure – but using two pumps in tandem allows Antec to use lower noise pumps and keep overall acoustic levels in check.

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This different approach to sealed loop design certainly has tangible benefits but is not without its negatives as well. Chief amongst them is the increased footprint of the fan and radiator. Even though Antec has opted for a ‘slim’ 27mm thick radiator the overall depth becomes about 95mm or 3.75” with everything attached which can cause installation issues in smaller cases. Antec has thoughtfully included the aforementioned offset adapters to help minimize any problems.

Unfortunately, by combining the pumps and fans into one cohesive unit, consumers will be unable to use aftermarket fans because there are numerous pieces of tubing connecting the radiator to the pumps which are in turn directly attached to the fans. In addition, the fans and pumps need to run in tandem so once fan speed is reduced for lower noise levels, the pumps will essentially move less water as well.

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The two included fans are a rated for 2400RPM and are rated for 50,000 hours MTBF so concerns over premature ‘pump’ death because of bad fan bearings are minimized. Performance is also quite impressive: 98CFM and 2.78mm of static pressure.

 

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Closer Look at the Kuhler 1250 (pg.2)

Closer look at the Kuhler 1250 (pg.2)

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The radiator uses a 27mm thick by 240mm long by 120mm wide design and features the newer 15mm offset for fan mounting. It also makes use of 12 water channels with a relatively dense number of folds per inch. Unlike the typical radiator which has as single inlet and outlet port, this one has two inlets and two outlets due to a design which pushes water from pump A into the radiator, through the first inlet and into Pump B upon which it moves ont to the water block.

This layout increases water pressure and velocity which can help augment efficiency. However it also has increased the number of failure points and potential leak points as there are now three times the number of tubing pieces, and two and half times the number of connectors versus a typical AIO design.

The tubing itself is the same Asetek has been using for a few generations now. It is thin yet flexible 3/8” OD tubing which is made from a low evaporative ‘rubber’ type instead of the older FEF style. There’s about 12 inches of length here which should be more than enough for most cases.

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The water block is also – for now - unique to the Kuhler 1250 and is Asetek’s latest generation design so there are no longer any large gaps along the perimeter where TIM can fill up, harden and make future clean-ups more difficult. Its installation process has also been upgraded and instead of an exterior tooth-like mounting pattern running along the circumference, the new design has the mounting points integrated directly into the body. This is a great improvement since it minimizes flex.

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Internally the water block has also been upgraded and improved with better efficiency to take advantage of the greater flow rate afforded by dual pumps. The base’s quality and finishing is also quite good.

Taken as a whole the Kuhler 1250’s design is a lot more controversial than previous Kuhler models, but at least Antec cannot be accused of simply copying anyone else’s design. This new cooler may have a similar Asetek foundation to many of the competition but it really has taken a radically different approach to things.

Antec also includes a piece of software called GRID which essentially allows you to control fan (and pump) speeds manually or put the Kuhler into one of two preset modes: Silent or Extreme. Unfortunately it decides when to work and when not to, sometimes neglecting to display fan speeds while other times refusing to accept a modification. Antec really needs to work on this before it becomes a viable control solution.

 

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Kuhler 1250 Installation (Intel / AMD)

Kuhler 1250 Installation (Intel)

After countless generations it appears that Asetek – or at the very least Antec branded Asetek units – have finally created an installation process which is easy and straightforward. With that being said anyone familiar with previous Asetek installation procedures will instantly recognize the Kuhler 1250’s since Asetek didn’t throw out the baby with the bath water. Rather, they have taken their old way of doing things and refined it. The end result is much improved and nearly as easy as CoolIT’s magnetic mounting installation procedure.

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The new and improved all in one backplate may still be plastic instead of metal but it has been completely redesigned and is much more robust. All you need do is choose the Intel labeled side, and insert the four threaded tubes into the proper socket slot. The nearest to the CPU socket is for 775, the center one is for 115x and the furthest ones are for 1366 and 2011 socketed systems.

The key to installing these correctly is to push until you hear an audible click sound as this is the small ring running around the outer edge of each tube engaging with the proper cutout in the plastic. Not pushing far enough will cause everything to fall out once the motherboard is rotated into an upright position. With this done the included double sided tape can be used to attach the backplate to your motherboard.

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Asetek’s new ring is now an all-in-one affair and is used for both Intel and AMD systems. Simply make sure all four corner brackets are in the correct location and then slide the ring onto the water block’s base. With a small clockwise twist the ring will engage and lock into position. The beauty of this design is the water block can be put into any orientation, neatly avoiding any installation conflicts.

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With the retention ring in place, it can then be secured to the motherboard with the four long spring loaded black bolts. This too is a much more straight forward proposition compared to previous generations as the bolts are not captured and easily removed.

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With all this accomplished, the radiator with its accompanying fans need to be installed which can be a bit of a frustrating process due to the unit’s overall size, especially when a second set of fans is called for. Due to the depth of this unit, you may need to use the included offset brackets to ensure the Kuhler 1250 doesn’t come in contact with the motherboard’s heatsinks.

As with all dual bay units the Kuhler 1250 requires a case that has dual 120mm exhaust ports. Most modern enclosures come with dual 120mm top mounts but this cooler requires the newer 15mm spacing so make sure your case supports this before installation progresses too far. If it doesn’t, a few modifications will need to be made.

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All that is left to do is plug in the various cables, and you will be done. Overall it may not be as simple or straightforward as CoolIT’s latest installation process, but the Kuhler 1250 is a very easy to install cooler and well above average in most regards.

AMD System Installation

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The AMD installation uses most of the same hardware as its Intel counterpart though this time the “AMD” settings are used. Install the four hollow tubes the same as you would on an Intel installation and using double sided tape attach the fully prepared backplate to the motherboard.

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Also like the Intel installation the very next thing you need to do is prep the metal top ring. This time make sure all four retaining arms are in the AMD configuration and then attach it to the waterblock in the exact same manner as before.

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With the brackets in place the installation continues to follow exactly along the same line as its Intel counterpart with the exact same minor caveat regarding fan spacing. Overall the Antec Kuhler 1250 is one of the more AMD friendly AIOs available on the market today.

 

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Stock Fan Performance Results

Stock Fan Performance Results

Please note in this section, we used Antec's GRID software to apply its two preset fan and pump speeds: Extreme and Silent. Extreme pushes rotational speed to between 2200RPM and 2400RPM while Silent reduces RPMs to ~1000.

As the name suggests the ‘Extreme’ setting is just that and has the pumps and fans running at full speed with no regard for noise or coolant temperature. Meanwhile, Silent is only concerned with keeping noise levels at a minimum.

As you can see when the fans and pumps are operating at maximum speed the results are very impressive. The increased water flow and water pressure allows this thin dual bay radiator to compete with the best of the best.

Unfortunately, once the pump speed is reduced – the largest side effect of combing fan and pump motors – the performance drops and drops noticeably. Fans simply are much more capable at running at less than full speeds, whereas small pumps don't like any setting besides flat-out. Even with two pumps running in tandem, the Kuhler 1250 just can't overcome this reality.

When you factor in the loss of aftermarket fans (which would have allowed for a lower noise solution) the end result is a rather mixed bag. If you do not care about noise the Kuhler 1250 would be a good choice. If you do, then other units such as the SilverStone Tundra Series, CoolIT H100i, or a dual 140mm radiator based design would be more suitable.

 

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Dual & Quad Fan Performance Results

Dual Fan Performance Results

Please note that the dual fan results are being included PURELY for information purposes to test how the Kuhler performs in comparative conditions. This setup should NOT be attempted by end-users. To accomplish this, we had to remove the stock fans and pumps from the radiator while keeping them plugged into the radiator. After this, we plugged in the aftermarket fans.

Quad Fan Performance Results

Please note that the dual fan results are being included PURELY for information purposes to test how the Kuhler performs in comparative conditions. This setup should NOT be attempted by end-users. To accomplish this, we had to remove the stock fans and pumps from the radiator while keeping them plugged into the radiator. After this, we plugged in the aftermarket fans.

The only real difference between these results and the ones above are quite simple: Antec sent us an additional pair of their stock fans so we could test a quad setup that wouldn't interfere with the warranty.

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As you can see, the results do prove that Asetek and Antec do have a very good design on their hands, one that is capable of competing against other manufactures' best models. This design does have merit and provides great cooling potential. Also,this thin radiator really doesn’t need quad fans to get optimal results since dual fans will provide most of the performance without the added installation issues associated with using a nearly 4.75" thick cooling device.

With that being said, if you do need more performance, we recommend buying two additional Antec fans rather than trying to give the Kuhler a warranty-destroying frontal lobotomy.

 

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Sound Level Testing

Sound Level Testing

While everyone "hears" noise differently there is one easy way to remove all subjectivness and easily compare different fans: use a sound level meter. This way you can easily compare the various fans noise envelopes without us colouring the results and see what fans fit within your personal comfort level. Of course, we will endeavour to try and explain the various results (which are taken at a 30 inch distance) to help you our readers get an even better understanding of how loud a cooler's stock fan is, but even if you discount our personal opinions, the fact remains numbers don't lie. All fans are tested with both voltage regulation / PWM turned off.

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The Antec Kuhler 1250 exhibits a Dr Jekyll and Mr. Hyde mentality in our acoustics tests. On one hand, it is one of the loudest All In One liquid coolers we have tested to date when used in Extreme mode since the fans and pumps are operating at full speed. It does however provide very good results at this setting so there's a definite trade-off.

On the other hand, Silent Mode brings about very low noise levels but the drop in performance is extreme.

Naturally, Antec's GRID software can help you balance out the factors mentioned above but will only do so when it decides to actually work. Until its bugs are ironed out, you may find yourself stuck at one of the presets.

 

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Conclusion

Conclusion

In a market filled with clones and copies of the same design with next to no distinguishing features, the Antec Kuhler 1250 dares to be different. Its outside the box thinking is exactly what the stagnant AIO marketplace needs and Antec deserves some credit taking such a large risk with their venerable Kuhler series. With that being said, its design works well in a number of disciplines but falls short in others.

Moving the pump off the water block is certainly not a new idea but the execution here is certainly unique. By utilizing two smaller and quieter pumps, Antec has found an elegant solution to the noise versus performance balancing act.

This innovative design twist may have the potential to change the marketplace, but its implementation tends to cause some rather significant challenges. By combing the pump and fan motor into one unit Antec has effectively increased the complexity of their design and made simple parts replacement more difficult. In one fell swoop this design decision also removes the ability to use aftermarket fans, kyboshing any modifications end users want to perform.

The synergy of pump and fan also directly ties each unit’s rotational speed to the other, which is an issue since they don’t scale in a similar fashion. For example, when the fan speed is lowered, the pumps reduce water flow, causing a two-pronged bottleneck. This leads to relatively minor RPM changes having a drastic impact on water and CPU temperatures.

As we saw in the tests, when the unit is running full speed, the Kuhler 1250 has the capability to run with the best AIO solutions on the market but it’s also one of the loudest we’ve tested. On the other hand, Silent Mode tanks performance. Finding a balance is the real trick here but that’s easier said than done. If you typically game with headphones on, the 1250 is an excellent choice.

This situation could have been somewhat mitigated by a good software solution that allows for fine-tuning and finding a balance between temperatures and acoustics. While Antec did include their GRID application, it’s far from stable, runs only when it wants to and randomly forgets your settings so we can’t consider it a viable option quite yet.

Antec’s Kuhler 1250 represents a departure from the cookie-cutter mentality of the All in One water cooling market and in most respects, is one of the better units currently available. Its out-of-box performance is quite good, installation is simple and Antec backs up their products with excellent customer service. Despite its limitations, with some much-needed software updates the Kuhler has the capability to become one of the best. Until that point it still represents a unique, innovative approach which deserves your attention.