X-bit labs

Zalman Reserator XT: Effective, Quiet, Stylish and Expensive Cooling Solution (page 10)

Category: Coolers

by Sergey Lepilov

[ 11/20/2007 | 02:01 PM ]

Thermal and Acoustic Performance

The Zalman Reserator XT was tested in two modes selected manually: Low (the speed of the 140mm fan is at its minimum of 850-900rpm, and the speed of the coolant is 0.5-0.75 liters per minute) and High (2000rpm and 2 liters per minute). If automatic speed regulation is enabled, then the Reserator XT is always operating at the minimum speed. The temperature of the coolant and the ambient temperature must be not high enough for the system to increase the speed of the fan and the performance of the pump. For example, the central monitoring window would report 31/27°C (coolant/ambient) under peak load and 27/24°C when idle.

Here is the first diagram that shows the temperature of the CPU that was being cooled by the Zalman Reserator XT and Thermalright Ultra-120 eXtreme:

Bravo, Zalman! I’m not a fan of the Korean firm, yet I can’t but praise its achievement: the Reserator is superior to the best air cooler by 10°C, their noise levels being comparable. It is the first time that I see such an overwhelming superiority of a serially produced liquid cooling system. Such systems used to be worse even than compared with less advanced air coolers.

The mainboard’s sensor reports an even more impressive difference:

Moreover, you can even drop the temperature by 6°C more (for benchmarking, for example) by selecting the maximum fan speed and pump performance. You get a 16°C advantage in terms of CPU temperature then, but the noise level isn’t very comfortable.

The noise comes only from the 140mm fan which is somewhat audible even at its minimum speed (850-900rpm according to the monitoring tools). The pump is absolutely silent in both operation modes. I guess its noise is just too weak to be heard amidst the loud noise from the fan at full speed.

Besides ordinary tests I compared water-blocks from the new Reserator XT and the previous model Reserator 2. They have ZM-WB5 and ZM-WB4 Gold water-blocks, respectively. There were the same two modes (High and Low) for the Reserator XT. The new water-block proved to be far superior to the previous model:

Note that if the Zalman Reserator XT came with the ZM-WB4 Gold rather than with the ZM-WB4, it wouldn’t have such an impressive advantage over the air super-cooler. As a kind of an announcement of an upcoming review, I can tell you that I also used this water-block to achieve a 24°C advantage over the Thermalright Ultra-120 eXtreme (with two fans)!

So, is this liquid cooling system preferable to air super-coolers in practical applications? I tried to find the highest CPU frequency with each cooler:

Not a very impressive difference, is it? The Reserator XT helps set a CPU frequency higher by less than 100MHz. This can hardly justify the fourfold difference in price. In the Reserator’s noisy mode the frequency gain was only 143MHz (at a voltage of 1.6875V) and I couldn’t increase the CPU clock rate further even when setting a higher voltage. Considering the peak temperature of only 62°C, this must be the CPU’s ceiling rather than a limitation on the cooler’s part. So, the Reserator XT may deliver more impressive results with other CPUs.