Verdict: Good-quality components, but fiddly to set up.
How much benefit you gain from water-cooling a PC depends on how much time and money you're willing to expend. For some people, water cooling is a hobby that deserves an equal amount of effort as you would apply to building your PC, involving the research of thermal transfer rates, the sourcing of esoteric bits and bobs, and hundreds of pounds' worth of equipment. If you aren't ready to dive in at the deep end, however (pun intended), you can opt for a kit composed of selected components that should work well together. The latest example of such a kit is the XSPC X2O Pro.
The X2O Pro offers all the basic components needed to cool a CPU using water. There's a 120mm radiator, a CPU waterblock, a pump submerged in its own cylindrical reservoir, plus ample amounts of flexible tubing.
A cheaper version of the kit, which drops the 'Pro' from its name and the reservoir from the box, is also available. The lack of a reservoir will impair ease of setup and maintenance, however, as reservoirs come in handy for filling and draining water-cooling systems.
The waterblock is a very simple-looking circular affair with a universal retention bracket for pretty much every CPU you might care to use.
Unfortunately, mounting it isn't especially straightforward. Four long bolts are needed to hold the waterblock in place, and you'll need to remove the motherboard from the case in order to thread the bolts through the back of the board. The block is clamped in place with spring-tensioned screws, making it hard to judge when enough pressure has been applied.
Cutting the 10mm OD PVC tubing with a sharp pair of scissors was easy, and thankfully, there was plenty of tubing to comfortably fit the kit inside our usual Cooler Master Stacker 830 thermal test rig case. The tubing connects with screw fittings, which provide a firm and watertight seal even if you tighten them using only your hand. Filling the reservoir was a little fiddly and required a funnel (not supplied). The next job was degassing the tubes and checking for leaks. Usually, you'd perform this task away from your hydrophobic motherboard, using a jumper to fool the PSU into powering up its rails. However, the pump of the X2O Pro is powered by a 3-pin header (the sort you'd use for a fan), so you need to either buy a Molex adaptor or test for leaks in the vicinity of your highly water-sensitive PC internals. Thankfully, we had a spare 3-pin-to-Molex converter to hand, and this is by far the safest option.
No PSU power jumper is supplied, so you'll have to make your own and jump the green pin with one of the neighbouring black ones. Once you've expelled all the air bubbles, you can power down the PSU, seal the reservoir and install the kit in your PC.
Unfortunately, the rear fan mount on the Stacker 830 is crowded, and we were unable to attach the radiator of the X2O Pro to the outside of the Stacker 830 using the method suggested in the manual (even when using the supplied L-shaped metal 80mm fan mount adaptors). As the radiator is larger than standard 120mm models, we were also unable to mount it to the internal side of the rear fan mount. With these positions out of commission, we had to install the radiator in some spare 5.25in external drive bays, with hot air blowing out of the front of the case. We're concerned by the fact that achieving an optimum mounting position could require case modding, although this could simply be a quirk that's unique to the Stacker 830.
The pump is of the low flow rate variety, and is submerged in its own reservoir, which also helps to dampen any vibration and noise emanating from it. The slow-spinning 1,700rpm 120mm fan on the radiator is also whisper-quiet.
Our thermal test rig comprises an overclocked quad-core Intel Xeon 3210 overvolted to 1.4125V, so it requires a fair amount of cooling. By keeping our CPU 7ûC cooler than the reference Intel heatsink, the X2O Pro managed to equal the performance of the £35 Tuniq Tower 120 air cooler at minimum fan speed. The £90 Swiftech H2O 120 Compact ran the same CPU just 6ûC cooler than the Intel reference CPU, so the X2O Pro is an effective, low-noise cooler.
At maximum fan speeds, the Swiftech cooled the CPU to 3ûC below the X2O Pro, although adding a more powerful fan to the X20 could easily close this gap. However, the X2O Pro costs just £70, so its cooling ability is good for the money.
Conclusion
The X2O Pro is a simple, good-quality water-cooling kit. However, rather than trying to make user-friendliness a priority, as Swiftech did with its H2O 120 Compact, the X2O Pro will probably cause you to get your hands dirty (or wet, at least). While the X2O Pro doesn't cut it as a n00b-friendly introduction to water cooling, it holds its own when it comes to cooling ability. This factor might make you want to persevere with it, in which case the extra £20 you save over the Swiftech kit will be a bonus.
For ease of use and installation, however, the Swiftech is the kit we'd recommend for those who want to use water cooling but are worried about the dangers involved. If you feel confident, however, this kit offers good cooling performance and low noise.
