Verdict: High-end cooling at a fraction of the price.

The H2O-220 Compact is a more advanced version of the H2O-120 Compact, the first all-in-one water-cooling kit worth buying. So how has Swiftech managed to improve on the H2O-120 Compact without sacrificing its compact dimensions and ease of installation?

The answer is simplicity itself - use a larger radiator. While the H2O-120 Compact only has a single 120mm-fan radiator, the H2O-220 Compact has a dual 120mm-fan radiator, so it should be capable of transferring much more heat from the CPU. However, the H2O-220 Compact isn't just a scaled-up version of the H2O-120 Compact; it also includes a few more accessories, such as 12V to 7V and 12V to 5V adaptors for the fans (the H2O-120 Compact only has two speed modes, 12V and 7V), longer tubing, 'k' splitters for branching off the tubing to add other waterblocks and an MCB-120 Rev 2 Radbox. Most cases aren't capable of internally mounting a dual 120mm-fan radiator, a problem that the Radbox solves by allowing you to mount the radiator/reservoir on the outside of the case on an 80mm, 92mm or 120mm fan mount. This makes the kit more versatile and, while you can buy the Radbox separately and add it to the H2O-120, it's good to see it included in this kit.

The Apogee Drive combined CPU waterblock/pump remains unchanged from the smaller kit. It's based on the Laing DDC pump so is very powerful, despite its compact dimensions. The Apogee Drive is compatible with almost all modern CPUs (apart from LGA 771 Xeons), and can be easily mounted on LGA775 CPUs by screwing it onto a backplate on the underside of the motherboard. This takes mere moments, making the Apogee Drive far quicker and easier to install than most waterblocks. That said, as the pump is mounted on top of the waterblock, its vibrations will be transmitted into the case, so it can be noisier than a separate pump, which is usually isolated from the case by a layer of rubber or foam.

As already mentioned, the cooling power is provided by a scaled-up combined radiator/reservoir called the MCR220-QP Res. This is a self-purging radiator, so air shouldn't build up in the plenum chambers over time, or if the radiator is installed at an unusual angle. However, as the reservoir is integrated into the radiator, you need to be gentle when pouring in coolant, otherwise it will bubble out. If you run into trouble, Swiftech supplies a small funnel and a well-illustrated colour manual to explain the installation procedure.

The two 120mm fans run at 12V by default, but if you find this too noisy, also included in the kit is a pair of 12V to 7V resistor cables, plus a pair of 12V to 5V adaptor cables. As with the H2O-120 Compact, the H2O-220 Compact also uses 3/8in ID tubing, and is supplied with a bottle of Hydrx anti-algae and corrosion inhibitor to mix with the water before pouring it into the reservoir.

As the H2O-220 Compact has the same waterblock/pump as that of the H2O-120 Compact, it provides a great example of the effect that radiator size has on CPU temperature. At 12V, the H2O-220 Compact cooled the CPU to 12ûC below the Tuniq Tower 120, 4ûC cooler than the H2O-120 Compact. However, the fans are pretty noisy at 12V, so we tested the H2O-220 Compact again with the fans slowed down. With the fans slowed to the 7V setting, the CPU ran 7ûC cooler than it did with the Tuniq Tower 120, and 5ûC cooler with the fans running at 5V.

The H2O-220 Compact is a perfect example of how size matters when it comes to water cooling, as it can have a massive effect on the components' temperatures. This means that thanks to its larger radiator, the H2O-220 Compact can cope with a heavily overclocked quad-core CPU much better than the smaller H2O-120 Compact, allowing you to overclock further or reduce the fan speed and noise.

In our opinion, this extra cooling and the flexibility it provides makes the £30 price premium for the H2O-220 Compact well worth paying. It also has a better accessories bundle, including longer tubing, the useful Radbox and 'k' splitters for adding extra waterblocks.

If you want to overclock your CPU to around 4GHz and haven't previously built a water-cooling system, or are put off by the cost, complexity and poor documentation of most high-end kits, the H2O-220 Compact is just the water-cooling kit to change your mind.

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