Want to kick your PC performance up a few notches? A good liquid cooling system moves heat from the CPU more efficiently than air cooling and can run substantially more quietly. Many PC performance enthusiasts have used liquid cooling for years, and it's easy to see why liquid cooling is a popular performance upgrade.

In the past, though, installing liquid cooling systems was not for the faint of heart. Once upon a time you needed to understand water blocks, radiators, pumps, and plumb. That's right: plumbing. High-end liquid cooling involved connecting tubing, ensuring that the tubing was properly sealed, and then filling up the reservoir with coolant. If you didn't achieve a proper seal, firing up the liquid cooler could lead to disaster, with coolant leaking all over your expensive PC hardware.

High-end customized cooling systems are still the only way to go if you want to cool all aspects of your PC, including graphics cards and even hard drives. But if you just want a better CPU cooler, the new generation of sealed liquid coolers offers an interesting alternative that's usually superior to high-end air coolers.

Why You Should Upgrade

If you're content to run with the stock Intel or AMD CPU cooler that ships with your CPU, that's fine--unless your CPU doesn't include a CPU cooler at all. In the later case you can plunk down $20 or so for a standard fan/heat-sink combo, but your CPU will run a little hotter and the overall noise levels will be higher.

For a little more money ($40 to $100), you could pick up a high-end air cooler. Most are quieter than a standard heat sink unit, but they tend to be much bulkier as well. And though they can be very efficient at cooling your CPU, some actually restrict airflow, particularly inside smaller midsize-tower cases. As a result of airflow restrictions imposed by a massive air cooler, key components such as graphics cards, drives, and even motherboard components may run hotter.

Cue the sealed liquid coolers. These coolers contain a tiny pump integrated into the heat-sink module. The heat-sink/pump module is connected to a radiator via factory-sealed tubes, so you never have to fill or refill the liquid. A modest amount of liquid coolant circulates via the pump between the radiator and the heat sink. The tubing is both flexible and well-constructed, so it takes a considerable effort to break the tubing and spill the small amount of liquid coolant.

The radiators are designed to fit into a standard fan mount (usually 120mm) on most PC cases. Fans attached to the coolers remove waste heat from the radiator. Note that some higher-end variants may support dual fans, improving airflow and cooling efficiency but also increasing system noise.

Most models in the new generation of liquid cooling systems for CPUs are fairly simple to install. In fact, they're often less difficult to install than high-end, fan-based CPU coolers, since they're more compact and fit into a wider range of cases. The most common issues that arise during installation involve the case-mounted radiator module, not the heat sink itself.

The two computers we'll use to demonstrate how to install a sealed-liquid cooler are Intel-based PCs, but the cooling systems support AMD-based systems as well, with only minor changes related to the mounting hardware. First, though, let's look at the two cooling products: the Antec Kühler H2O 620, and the Corsair H60.

Antec Kühler H2O 620

The Kühler H2O 620 sells for around $60, though you can probably find it for a little less if you shop carefully. Its designer, Asetek, is also responsible for the Intel RTS2011LC liquid cooling system.

The heat-sink/pump module is round, as are most other Asetek-based designs, with a ring-based mounting setup.

The included bag of hardware contains different mounting plates, suitable for installing the cooler onto an Intel or AMD-based motherboard.

Corsair H60

The Corsair H60 is another basic, single-fan cooling system. This product usually costs about $60.

Designed by CoolIt technologies, the H60 attaches to a CPU a little differently than the Antec cooling system does.

The Corsair H60 heat sink is a tad easier to attach than the Antec, but neither is particularly difficult. Now let's look at the installation process.

Before You Install

Before you begin installing either of these liquid CPU coolers, confirm that your system's case and motherboard can support the following components:

  • A 120mm fan mount on the case to accommodate the radiator. Usually, this fan mount will be in the rear of the case, but some smaller cases may locate it on the top. Given the length of the sealed tubing, it's almost impossible to install the radiator in the front of the case. While some cases have fan mounts on the side panel, I'd strongly recommend against installing the radiator on the side panel, which would make removal of the panel difficult at best.
  • For the Corsair H60, two motherboard-based fan connectors. You'll need one fan connector for the pump, and the other for the fan. Make sure that you have two fan power headers on the motherboard, in close proximity to the CPU socket (within 4 to 5 inches of it).
  • Space for a bracket on the underside of the motherboard. If your case doesn't have a cutout in the motherboard tray for mounting the bracket, you'll have to remove the motherboard to install the brace.

You'll also need to remove a couple of components before you can begin installing the new cooling system.

First, you must remove the 120mm case fan (if you have one) from the future location of the radiator.

Second, you must remove the existing CPU heat sink.

If you have a stock Intel cooler, removing it is simple. Using a flat-bladed screwdriver, rotate the mounting latches about one-half turn counterclockwise and pull each latch straight up until you feel it detach from the motherboard. After detaching all four latches, remove the heat sink.

If you have a high-end air-cooled CPU heat sink, it may have a back plate on the motherboard to help support it. Remove that plate prior to installing the underside brace for the new cooler.

Now you're ready to install the new cooler.

Case Study: Antec Kühler H2O 620 Installation

I installed the Antec Kühler H2O 620 into a system running an Intel Core i7-960 CPU on an X58-based motherboard. My system had previously sported the standard Intel heat sink, and the CPU constantly ran on the hot side. Though the processor never overheated, the fan would spin up quite noisily when the CPU was under load. Here are the steps:

1. Attach the bottom brace to the motherboard. The Kühler ships with different braces for AMD and Intel CPUs. The Intel brace has three slots for accommodating the actual mounting nuts. I slipped the nuts into the slots for socket 1366. Use two slivers of double-sided sticky tape to help the brace adhere to the bottom of the motherboard so that it won't drop out of reach when you install the circular mount. (I ended up using tape on one side, however, due to the presence of lots of solder points on the rear of the motherboard.)

2. Attach the radiator to the case. The mounting screws for the radiator will run through the fan, and then screw into the heat sink, sandwiching the fan between the radiator and the case. Be sure to align the fan so that the air travels from inside the case to outside. Arrows on the fan's sides indicate direction of air movement.

3. Screw the retention ring into the bottom brace, through the heat sink mounting holes surrounding the CPU socket. When you attach the retention ring initially, turn the screws only enough to make a firm connection; don't screw them down tightly yet.

4. Slip the Kühler H2O 620 heat-sink pod through the retention ring. Tabs on the heat sink will slip between retaining tabs on the ring. Rotate the heat sink slightly, until the heat sink tabs align with the retention ring taps. Then, while holding the heat sink firmly with one hand, gradually tighten the screws, alternating between them every few turns, until all four screws are firmly seated.

(If you plan to install the Intel version--the RTS2011LC--onto a socket 2011 motherboard, you may want to hold the heat sink in place, lower the detached retention ring over the heat sink so that the tabs align, and then screw it into place. Clearance between the retention ring and heat sink on the RTS2011LC is very tight.)

5. Once the heat sink and the radiator are attached, connect the radiator-fan power connector and the heat-sink pump connector via an adapter link. Then connect the single power connector to the heat-sink fan power header on the motherboard. The Kühler H2O 620 only uses the CPU power connector.

After hooking up the Kühler H2O 620 power, I fired up my system to test its performance. Previously, with the stock Intel cooler, idle CPU temperatures hovered at around 55 to 56 degrees Celsius. Now it runs at about 40 degrees Celsius, and the entire system is far less noisy.

Case Study: Corsair H60 Installation

My test system was running a custom CPU cooler, so I had to remove the cooler and underside mounted retention bracket. You may have to do the same someday, so here's how to proceed. This particular system is based on an Intel Z68 chipset running a Core i7-2600K CPU. The H60 doesn't come with double-sided tape, but friction from the mounting pillars held the underside brace in place.

1. To be safe, attach the first screws while the case is standing vertically. The Corsair H60 heat-sink module attaches to mounting screws, which themselves screw into the underside mounting plate.

2. Carefully align the heat sink mounting holes. It's easy to warp the mounting pins slightly, but doing so will result in cross-threading the mounting screws. Be sure to alternate the turns of each screw, rather than screwing each one all the way down before starting on the next screw.

The original air cooler on this PC was pretty effective, so the CPU idle temperature in this instance dropped only a few degrees during testing, from about 43 degrees Celsius to about 40 degrees Celsius. But the motherboard temperature dropped several degrees as well. And as with the previous system, noise levels were noticeably lower.

Final Thoughts

Since these units contain moving parts and liquid, you might be concerned about reliability, pump failures, or leakage. The Antec Kühler H2O 620 offers a three-year warranty, while Corsair ups the ante with a five-year warranty on its H60. In both cases, overall reliability is highly likely to exceed the warranty period. As Corsair's FAQ for the H60 puts it, "The expected lifespan of the average unit is significantly longer than the warranty period."

If the pump fails, the effect is no different from that of having a normal air cooler fan fail: The CPU will overheat and the system will shut down. There's no reliable data on the frequency of coolant leakage, but I have heard of instances where coolant leaked out of the tubes and cooked the motherboard. Nevertheless, with thousands of these coolers in place and big names like Intel jumping into the market, leakage is unlikely. Just make sure you don't bend the tubes into unusual angles or around components that are likely to cause tube damage.

I've been using variants of these sealed liquid coolers for two years now, with no major issues or failures. They aren't as noisy as most air-cooling alternatives, and they're priced about the same as high-end air coolers. So if you want a quieter system but require a high-performance CPU, it's worth your time to install a high-quality sealed liquid cooling system.