Verdict: A great first foray into the potentially scary world of water cooling.
Mercury, the planet closest to the sun, spends a lot of its time at 180ûC below freezing. Even for a particularly hardy Newcastle United fan, that's chilly. But before you become too excited about the sub-zero cooling potential of Gigabyte's new 3D Mercury chassis, you should bear in mind that during Mercury's summer months, the temperature can rise to as much as 425ûC, which is almost the melting point of a CPU, never mind its thermal shutdown temperature.
Cosmological digressions aside, you're right to expect something special from a £235 computer case. The last case we reviewed around this price was the Zalman FC-ZE1 Fatal1ty Champion Computer Enclosure, which offered unsurpassed build quality. Gigabyte has taken a different approach; instead of a ton of aluminium and fancy, laser-etched logos, the 3D Mercury has an integrated water-cooling kit.
While not strictly necessary - a £30 heatsink and fan, such as the Tuniq Tower 120, can cool a quad-core CPU just fine - water-cooling kits have the advantage of looking great, especially when combined with tasteful lighting. You should also see a more efficient dispersal of thermal energy, as the heat is conveyed directly to an exhaust radiator that uses fewer fans than a conventional air-cooling arrangement. The downside is that if you don't know exactly what you're doing, you end up with a very expensive fish tank and an odd blue or green water stain on the floor. With that in mind, there are many 'first-timer' water-cooling kits on the market, and this is essentially what the 3D Mercury is.
The case is mostly made from brushed aluminium, which is a good-looking material, although the thin side panels feel a little flimsy. In a diversion from the usual shouty Gigabyte style, as typified by cases such as the 3D Aurora, the 3D Mercury is tall and very simple. It's reminiscent of Cooler Master's early incarnations of the epochal Stacker, but with a large side window. It's also available in black, which should provide an effective background for the glowing dark blue flow meter and fill-level indicators on the front of the case.
There's plenty of space inside for a hefty dual-graphics card system, and the case is long enough to accommodate an E-ATX motherboard. There are four 5.25in screwless optical drive bays, two 3.5in floppy bays, and space for five hard disks in a rotated, screwless cage that's identical to that of previous Gigabyte cases such as the 3D Aurora. In fact, the biggest criticism of the internal setup of the case is that we've seen it all before. This isn't a bad thing in itself, but we've found that the rotated hard disk cage reduces the effectiveness of the case's intake fan.
Cooling
The reason for the towering height of the 3D Mercury is easily explained; sliding off the roof reveals a mechanical construction straight out of 'Back to the Future'.
The water-cooling kit comprises a single 120mm radiator, which is a far cry from the custom quadruple radiators found inside this year's Vadim Dream PC, but nevertheless a neat unit. In order to maximise the cooling potential of the radiator, Gigabyte has fitted it with two 120mm fans; one fan pulls air into the radiator while the other pushes it out, thereby directing a reassuringly strong flow of air out of the large vent at the rear of the case. However, using a dual 120mm-fan radiator and mounting it horizontally (with fans blowing upwards), then cutting a vent in this upper chamber would make the 3D Mercury infinitely more upgrade-friendly, although it would add significantly to the cost.
There are some very neat touches in the case, however, especially for those who appreciate simplicity. Most of the wiring and tubing is neatly tidied away, leaving space to easily fit your components. A large funnel on the top of the case makes filling the reservoir and topping it up an easy task - you simply unscrew the large plug (which is reminiscent of a petrol cap) and pour in the liquid, then screw in the cap again afterwards.
Gigabyte provides 1.2 litres of pre-mixed anti-algae and anti-corrosion blue coolant, and setting up the system is very easy. All the tubes and fittings necessary for cooling the CPU are already fitted. You just fit the CPU waterblock - a matter of tightening four screws into a backplate - and then top up the reservoir as the pump pushes coolant around the system. Refreshingly, this worked first time around; there were no leaks, and the system was effective at disposing of air bubbles trapped inside the components. While the tubing is PVA, rather than the less porous Neoprene or Norprene, it's UV-reactive.
One niggle is the fact that Gigabyte doesn't include anything with which to jump start your PSU, and therefore fool it into thinking that it's plugged into a motherboard). With this in mind, the solution is to make your own jumper using some spare wire. Find the green wire on the ATX connector block and short it with one of the black ones on either side. People who don't know how to do this will have to test a water-cooling setup with power running through their systems, which is a potentially fatal risk (to your PC, at least).
The speed of the radiator's fans can be adjusted depending on how much you're overclocking the system, with the fastest speed being way too loud for comfort. The lowest fan speed setting was quiet, however, and even at medium speed, the pleasant hum of the pump was the loudest aspect of the system.
We installed our standard thermal test rig in the 3D Mercury to directly compare its cooling performance with that of the Swiftech H2O 120 Compact water-cooling kit. With the two fans whirring at their top speed, the 3D Mercury cooled the overclocked and overvolted Intel Xeon X3210 to 8ûC cooler than the Intel reference cooler, and to 5ûC and 2ûC cooler at medium and low fan speeds respectively. This compares well with the Swiftech kit, which cooled the same CPU at the same settings to 10ûC cooler at its top fan speed, and 6ûC cooler at its lower setting. Considering that the 3D Mercury is a lot easier to deal with and costs roughly the same amount as the Swiftech H20 120 Compact, that isn't bad at all.
If you want to add another waterblock to the circuit, the two spare three-way splitter valves - complete with off/on taps - allow you to add the necessary extra tubing without draining the entire system. This is a godsend, and vastly easier than adding extra waterblocks to a self-made water-cooling setup. However, the extra tubing isn't supplied, so you'll have to make sure you buy the right kind (Gigabyte claims it's 'Automobile standard', whatever that means - we measured it as being 10mm ID/13mm OD tubing. However, adding extra waterblocks may mean that you'll need to add extra radiators, unless it's to water-cool a minor component such as the Northbridge. There are two 120mm fan mounts at the rear that make likely candidates for a dual 120mm radiator, plus pre-cut holes towards the base of the rear of the case. However, it would have been better if there were radiators included in the first place.
Conclusion
Rather than being a simple PC case, the Gigabyte 3D Mercury asks you to buy a water-cooling kit as well, so you should expect both the case and the cooling system to be worthy of your money. In many ways they are, although there are also caveats to consider. The spacious case is well laid out and one of Gigabyte's better-looking efforts but, much like the 3D Aurora, the airflow through the case is hindered by a rotated hard disk cage. Similarly, while the water-cooling kit is generally quiet and very easy to set up, the single 120mm radiator limits its cooling performance.
For £80, the Antec P180 is a better case than the Mercury. Also, the Swiftech H20 120 Compact is a better water-cooling kit than the kit used in the Mercury. Combining the two saves you £65 and means you can treat yourself to a game. However, you might not get around to playing it for a while as setting up something even as simple as the Swiftech kit is more effort than using the 3D Mercury. The Gigabyte 3D Mercury is an innovative and mostly successful attempt at 'easy' water cooling, and a good option for your first steps into water cooling.
