Water in a computer? Sounds crazy, but enthusiasts often do crazy things in the name of performance. When it comes to moving heat, density is king, and water beats air by several orders of magnitude in volumetric heat capacity. Now, with that physics-jargon-laden sentence out of the way, let's talk a little more about how water cooling works.
Anyone in the cooling business should be familiar with the benefits of using liquids as an exchange medium. This is especially true in the automotive industry, where fluid-cooled engines are far more common now than air-cooled varieties. Liquid cooling is also picking up steam (ha!) in the HVAC industry, where geothermal systems utilize water's excellent thermal characteristics to harness the constant temperature of the Earth. Thanks to the use of a superb heat mover like water and a heatsink as large as the Earth itself, common heat pumps and blowers can manage the temperatures of entire buildings with huge increases in efficiency over traditional furnaces and air exchangers.
In a computer, the principles are all the same, but the scale is a little smaller. Sure, some people go nuts and build systems large enough to cool a motorhome, but even most hardcore enthusiasts will be happy with anything that enables an overclock that makes their forum buddies jealous. The quest for higher overclocks drove gutsy early tinkerers to cobble together water cooling systems from equipment normally used in all kinds of different areas. Popular components included small car radiators, laboratory-grade tubing, and water pumps meant for small ponds and fish tanks. These folks still needed to transfer heat away from the CPU, and since few had the means to mill custom water blocks, it's no surprise that some manufacturers picked up the slack, offering designs of their own.
Water cooling gained popularity as more PC-specific components entered the market, but folks were still piecing together systems using parts from different manufacturers. To make things a little easier, cooling companies starting bundling all the parts one might need into complete kits. These became quite popular, as they also guaranteed component compatibility. Assembly was still required, though. That doesn't usually faze enthusiasts, but when you're dealing with conductive liquid flowing around the internals of an electrically charged PC, securing tubing and checking for leaks can be a little harrowing.
In recent years, some manufacturers have begun dabbling with factory-sealed kits that take much of the assemblyand paranoiaout of water cooling. These units are often just as easy to install as traditional air coolers, and they don't cost all that much than some high-end heatsink towers. We had our first real look at such a design when we pitted CoolIT's Domino ALC against a range of traditional air coolers back in June. The Domino cooled well and was easy to use, but its fan noise put us off a little. Today we've corralled a similar factory-sealed unit from Corsair, the new Hydro Series H50, to see how it compares.
So what's all in an all-in-one water cooler?
Corsair's H50 isn't quite as all-in-one as the Domino, but only because the included 120-mm fan doesn't come pre-attached to the radiator. Other than that, the H50's components require no assembly.
Instead of putting the pump right next to the radiator, Corsair embeds it inside the water block assembly. While this makes the radiator lighter and therefore easier to install, it does burden the motherboard with a little extra weight. Thankfully, the mounting hardware includes back plates to alleviate any extra stresses on the motherboard. Mounting hardware is only provided for Intel LGA775 and LGA1366 sockets, though. AMD-compatible brackets (shown on the left in the picture below) are sold separately and cost $3 online. Lynnfield-compatible mounting hardware will apparently be available soon on the Corsair website at a similar price.
Each retention package comes with a motherboard back plate, retention ring, and four spring-tensioned bolts to hold everything together. Four long screws, complete with washers, secure the fan and radiator to an enclosure's rear 120-mm fan mount. The washers are basic metal ones, which is somewhat surprising considering the popularity of vibration-dampening rubber washers in not only cooling products, but cases, as well.
The H50's all-copper water block surface is large enough to provide plenty of contact area for modern processors. It's also coated with a putty-like thermal compound, further simplifying the installation process. Factory-sealed and semi-flexible tubing leads right out of the top of the water block assembly, stretching a full 11 inches before you get to the radiator.
Installing the Corsair cooler is a two-stage process, but it really doesn't matter which step you do first. To secure the water block assembly, I found it easiest to half-tighten the retention ring to the back plate before orienting the block to slip through the ring's circle of teeth. Once past the teeth, the entire water block assembly can be rotated to anchor it under the ring, after which tightening the bolts locks everything into place. Compared to other locking mechanisms I've worked with, Corsair's approach with the H50 is both effective and simple. You do have to remove the motherboard to secure the retention bracket's back plate, though.
To fasten the H50's radiator, the four long screws are run first through the case and fan before anchoring in the radiator and securing everything in place. Corsair recommends that the fan be oriented as an intake to keep the coolest air flowing over the radiator fins, which makes a certain amount of sense. The amount of heat transferred from one medium to another depends on the difference in temperature between them, and the air outside your case is likely to be cooler than what's circulating inside. Bear in mind that if you're making changes to the orientation of any case fan, it might be necessary to adjust the orientation of others to maintain a good system airflow pattern. If you switch a filtered intake to exhaust air from the case, you might be able to move its filter up to the H50's fan mount.
With the H50's two main components in place, all one needs to do is connect the power. Instead using a control module, Corsair feeds power to the H50's pump and fan separately. The four-pin fan lead is designed to plug into a motherboard header, and it will play nicely with temperature-based automatic fan speed controls. However, the pump's three-pin connector must be connected to a power source that provides a constant 12 volts. The pump's power cord is only 7" long, so you might run into trouble reaching an appropriate header on your motherboard. There's more reach with the fan's power connector, which measures a lengthy 11 inches.
Before getting into our test results, I should take a moment to point out that the H50 doesn't take up all that much space inside a system. Modern motherboards usually keep the socket area relatively clean, knowing that rear exhaust fans are common. Many of today's larger air coolers still manage to crowd the socket area, coming quite close to the side panels in some cases. That shouldn't be a problem with the H50, whose footprint is really quite modest. The fact that users can easily change the water block's orientation also adds a measure of flexibility, since the orientation determines where the 11 inches of tubing starts.