Zalman Reserator review

Water-cooling systems have traditionally used a fan to cool the radiator through which warm water passes. But Zalman's Reserator is the first not to use a fan at all; the massive blue reservoir is passively cooled. The Reserator functions as a very effective radiator, thanks to the multiple fins bristling from its 60cm, 6.5kg tubular core. The fins give it a huge surface area far in excess of the in-case radiators of normal water coolers, quickly dissipating the heat from water as it returns from the CPU block and obviating any need for a fan.

The Reserator's peculiar name is a clumsy hybrid of reservoir and radiator. Luckily, the design itself is anything but clumsy, and combining the two makes things both simpler and quieter. Only the pump makes noise, and even the Mafia couldn't have made that disappear more effectively. It's not quite sleeping with the fishes, but it is submerged at the bottom of the tank.

To draw heat away from the CPU, the Reserator uses Zalman's colossal ZM-WB2 water-block, which has been produced to the same high standards as the Reserator itself. The pure copper base is actually gold plated: gold has extremely high thermal conductivity. The ZM-WB2 is compatible with most desktop processors, including the Pentium 4, Athlon XP and both the standard and FX varieties of the Athlon 64. The block is held in place by an arm clamp that pushes it securely down onto the CPU. After installing the ZM-WB2, you'll need to cut the supplied 3m of tubing to length and connect them to nozzles on both the ZM-WB2 and Reserator. The seals were secure, and we didn't experience any leaks. The Reserator then needs to be filled with 2.5 litres of de-ionised water.

Since the Reserator is powered directly from the mains, you can run it independently of the PC for testing. There's also an in-line mechanical flow meter to help establish that the system is working correctly; an orange indicator inside a clear tube flutters rapidly to show that water is flowing through the system - a simple but effective device.

We overclocked the 3.2GHz Pentium 4 in our test rig to 3.32GHz to provide a sufficiently toasty thermal challenge. With the system idle in Windows XP, the Reserator brought down the temperature of the CPU 3C cooler than with a stock Intel heatsink and fan combination. When we loaded up the RealStorm real-time ray-tracing benchmark to really heat things up, performance differential was far more marked: the Reserator-cooled chip was 12C colder than the stock Intel design; an excellent result, especially since it's achieved in virtual silence.

The Reserator is both a hugely imposing and eye-catching piece of design and, more importantly, a damn good water-cooling system. But it's the silent operation that proves the best part. Yet again, Zalman has produced a great piece of kit.

Author: Alex Watson