by Sergey Lepilov
11/20/2007 | 02:01 PM
Showcased in early spring at CeBIT 2007, the Zalman Reserator XT active liquid cooling system has finally reached our labs. We are glad we can offer you our review of it and we want to note right away that Zalman has for the first time stepped away from its fan-less cooling concept embodied in the Reserator 1 (see our article called Aesthetic Water Cooling Solutions: Zalman Reserator 1, ZM-WB2 Gold and ZM-GWB1), Zalman Reserator 1 Plus (see our Zalman Reserator 1 Plus Liquid Cooling System Review) and Zalman Reserator 2 (see our article called Perfect Silence: Zalman Reserator 2 Fanless Liquid-Cooling System Review).
The new system employs a 140mm fan with a controllable rotation speed. This is not the only difference of the new Reserator from its predecessors, though. It features several innovations that are going to win wide recognition among overclockers of this world.
The new liquid cooling system from Zalman comes in a huge black box. The face side of it shows a full-size photo of the cooler’s main block:
The box is heavy and bulky – you may find it difficult to carry it home by yourself alone. Besides the photo, there is a list of key features on the face side of the box. One of the sides reports the product specs and more features.
When you open the cardboard box, you see a foam-plastic cover of the interior:
A user guide and a flexible pipe lie on that cover. The pipe is 4 meters long with an internal diameter of 8mm and 2mm walls.
The next tier of packaging is concealed under the plastic cover:
There are a few compartments here that contain a CPU water-block (Zalman ZM-WB5), cable to connect the main block, wire to close PSU contacts, anti-corrosion concentrate (Zalman ZM-G300), bracket for the back panel, clamps, and a pipe with two fittings to degas the system.
Below this tier you can find the system’s main unit:
It is fixed in a foam-plastic base. Coupled with the thick cardboard, this protects the device from possible damage quite securely.
I guess you have already noticed that the new Reserator comes without a GPU water-block as opposed to the previous Reserator models. The recommended price of the new cooler is $400. Let’s see how functional and efficient it is, beginning with its main block.
The main block of the Reserator XT comes in two colors: silver (the manufacturer calls it “titan”) and black. We’ve got the black version:
This large 350x210x180mm box is as heavy as 7 kilos. It is made from anodized aluminum. The cooler’s front panel catches one’s eyes immediately:
There are three highlighted indicators, a large controller of the fan speed and water flow, and three buttons on the panel. I’ll describe their functionality in the Assembly section. There are slits in the sides of the unit you can see dense ribs of the radiators through:
A water flow indicator is on a side panel, too. The blades of the indicator are rotating if the assembled and filled system is operating properly.
The higher the speed of the water flow, the faster the indicator is rotating. The opening of the system’s expansion tank is on the top of the main unit:
The rear panel has input and output fittings, a power connector, and a grid to exhaust the hot air from the radiators. You can see a 140mm fan through that grid.
My only gripe is that the grid is not made from wire. It would be smaller and present less resistance to the air flow then. I guess the noise would be lower with a wire grid, too.
There are four rubber feet on the bottom panel for the main unit to stand firmly.
Trying to take that thing apart, I managed to remove its rear panel with the fan:
The interior design is very interesting and original.
There are two radiators at the sides of the box, each pierced with the pipe six times. The expansion tank is fastened to the top panel in the center of the box. Note that its sides are ribbed to reduce the temperature of the coolant. Under the tank there is a low-performance pump (300lph, 1.8m max head). The same pump (probably manufactured by Eheim, too) is employed in the Zalman Reserator 2. All the components of the system are connected by means of flexible pipes with clamps.
The 140x25mm fan installed on the rear panel exhausts the hot air out of the main block. Its speed is regulated automatically or manually within 900 to 2000rpm according to the monitoring tools (a speed range of 500-2000rpm is declared in the specs). The two radiators get cool air through the slits in the side panels. Each radiator is just the right size for two 120mm intake fans – this modification came to my mind instantly – but you have to dismantle the whole system and think about how to power the fans up. The fans can be installed on the external side of the radiators, i.e. on the outside of the main block, but this simple-to-implement solution will spoil the exterior design of this stylish system. Moreover, the fans are going to be quieter inside the case. So, there is something to work on yet, I think.
The Reserator XT comes with the ZM-WB5 water-block that represents the fifth generation of CPU water-blocks from Zalman. Overclockers have been rather skeptical about Zalman’s water-blocks, blaming them for primitive design and an inadequate price/performance ratio. Let’s see what Zalman has come up with this time around.
The water-block is shipped in a transparent plastic package. It gives you a view of the water-block itself and of two pairs of clamps included with it:
There is a small box with accessories in the top of the package. It contains the following:
The water-block measures 63x63x40mm at 160g of weight. It has a copper base and an aluminum cap with two fittings:
The fittings have a double diameter, allowing to use pipes with the following diameters (external x internal): 14x10mm, 13x10mm, 13x9mm, 12x9mm, 12x8mm, 11x8mm, and 10x8mm.
The base and cap of the water-block are sealed with a warranty stamp but you can judge the internal design of the water-block by the photo on the packaging:
So, the Zalman ZM-WB5 has 144 cylindrical needles. To remind you, the previous version of the water-block (Zalman ZM-WB4 Gold) had a completely different internal design (more primitive, in my opinion).
I’ll check the efficiency of the new water-block in comparison with the previous version later on. Right now you can have a look at the water-block’s base:
It is ideally flat and polished off. I just can’t find a suitable laudatory epithet to describe it. The new water-block can be mounted on LGA775, Socket AM2 and 754/939/940. It doesn’t support Socket 478. To install the ZM-WB5 on a platform for AMD K8 CPUs you should secure the included clip on the nut of the central fitting and hitch it to the teeth of the standard retention frame. For LGA775 mainboards you should use a plastic back-plate, a frame and two separate fastening clips:
The installation process is described in more detail in the enclosed guide (a 0.9MB PDF file). The water-block presses very hard on the CPU heat-spreader while the fastening mechanism prevents it from rotating.
Prior to connecting the water-block to the main block with pipes, you should fill and degas the system. You need 1 liter of distilled water for that. The bottle with concentrated anti-corrosion liquid included into the kit is the same as was included with the Reserator 2 and has a volume of 250 milliliters.
Polypropylene glycol and anticorrosion additive are the main components of the liquid. The label on the bottle informs you that the liquid keeps its properties for 1 year and has a freezing point of -9°C. You must dilute it with 1 liter of distilled water, thus obtaining a total of 1.25 liters of coolant.
Then you should connect the main block to the power source. The power cable of the new Reserator ends in a Molex connector that is to be attached to your PSU.
The connection and degas process is illustrated as follows:
So, the Zalman Reserator XT is supposed to be started up using the same wire as the Reserator 2. This wire closes two contacts of the PSU’s 24-pin power connector. I did it in a simpler way, though. I just plugged the Reserator’s Molex into the PSU and started up an assembled system case with an air cooler on the CPU. After a few starts and stops (the manual recommends 3-7 cycles 10 seconds long) the radiators of the cooling system get filled up as indicated by the liquid in the pipe:
Then you install the water-block on the CPU.
The manufacturer recommends installing the ZM-WB5 in such a way that the central (input) is below the output one:
It is only in this position that the water-block is filled up fully, which ensures the maximum efficiency, according to Zalman.
Then you only have to connect the Reserator’s main block and the water-block with pipes (you should have removed the fittings from the degas pipe and inserted them into the ends of the water-block pipes before that), connect the Reserator’s power cable, and start up your system case. As opposed to the Zalman Reserator 2, the pipes get filled almost immediately when you begin to degas the system, and there are no bubbles in them left after a few minutes of operation.
The position of the Reserator’s main block relative to the PC case is also specified in the manual.
So, for the system to operate with maximum efficiency, the Reserator XT must be placed on the system case or right next to it. I chose the latter variant for my tests:
I put the Reserator 2 on a box for it to be on the same level with the system case.
The Reserator XT always starts up in automatic mode, i.e. the speed of the fan and coolant depend on the temperature. I couldn’t find a way to make it start up in manual mode, so I always had to switch the operation mode with the central Auto/Manual button (I guess the system cannot be started in manual mode at all). The two other buttons change the indication between Celsius/Fahrenheit and disable the highlighting of the displays. If you hold the latter button pressed for 5 seconds, the system is reset if it has started to emit a warning signal (for example, when there is not enough coolant or when the temperature of the coolant has reached 60°C).
Above the three buttons there is a controller of the speed of the fan and water flow (in other words, of the pump performance). Below are three monitoring indicators:
The left, arrow-like, indicator shows the speed of the fan in thousands of rotations per minute. I think a digital indicator would be better, though. The same goes for the rightmost indicator that shows the current speed of the coolant in liters per minute. The large central display reports the temperature of the coolant (the top number) and the ambient temperature. It also shows an icon that indicates the operation mode (manual or automatic) of the Reserator XT.
The assembly and installation guide can be downloaded from the manufacturer’s website (a 1.29MB PDF file).
The specifications of the new liquid cooling system from Zalman are listed in the following table:
The Zalman Reserator XT system and its opponent were tested in a closed system case with the following configuration:
The quad-core CPU was overclocked to the maximum stable frequency it had with the air cooler. That was 3483MHz. The core voltage was set at 1.6625V in the mainboard’s BIOS.
CPU-Z, SpeedFan and Everest reported a core voltage of 1.59V at that. The memory voltage was increased to 2.1V. The other mainboard voltages were left at their defaults.
All tests are performed in Windows XP Professional Edition Service Pack 2. SpeedFan 4.33 is used to monitor the temperature of the CPU, reading it from the CPU sensor.
The CPU is heated up by means of OverClock Checking Tool version 1.1.1 in a 24-minute test during which the system remains idle in the first and last 4 minutes for the temperature to stabilize.
The mainboard’s automatic fan speed management (Q-Fan technology) is disabled for the time of the tests. The thermal throttling of the Intel Core 2 Quad processor is controlled with RightMark CPU Clock Utility version 2.30. Our CPU begins to skip clock cycles on reaching a temperature of 82°C and higher.
I perform at least two cycles of tests and wait for 20 minutes for the temperature to stabilize during each test cycle. The maximum temperature of the hottest CPU core in the two test cycles is considered as the final result (if the difference is not bigger than 1°C – otherwise the test is performed once again). Despite the stabilization period, the result of the second cycle is usually 0.5-1°C higher with the air cooler. The results of both tests were identical with the liquid cooling system.
The ambient temperature was monitored by means of an electric thermometer and remained at 23.5-24°C during the tests (marked with a red line in the diagrams). The fan rotation speeds are shown in the diagrams as reported by SpeedFan.
The noise level of each cooler was measured according to our traditional method. The subjectively comfortable level of 36dBA is marked with a dash line in the diagram; the ambient noise from the system case, without the CPU cooler, was about 34dBA when measured from a distance of 1 meter.
The Zalman Reserator 2 was tested in our labs in comparison with the Enzotech Ultra-X cooler. And now, the new Reserator is going to be compared with a more formidable opponent. It is the Thermalright Ultra-120 eXtreme with two high-performance Scythe Minebea fans (4710KL-04W-B29) for intake and exhaust. Of course, the price of the air cooler is going to be only one fourth that of the recommended price of the Reserator XT even with the two rather expensive fans. However, none of liquid cooling systems we have tested so far could match the performance of the competing air cooler. Let’s see what we have this time around.
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.
The new liquid cooling system from Zalman is a definite success. For the first time in our tests a liquid cooling system has managed to outperform an air cooler. The Reserator XT was better by 10°C than the Thermalright Ultra-120 eXtreme (with two fans) in my tests. It also won the test of the maximum CPU frequency while being within comfortable limits in terms of noise. Zalman’s progress in designing water-blocks is especially praiseworthy. My tests suggest that the new ZM-WB5 water-block is 7-8°C more efficient than the ZM-WB4 Gold under peak CPU load.
I wouldn’t say that the recommended price of $400 is too high. Many experienced users of liquid cooling systems will tell you that a good solution of that type cannot be cheap. Perhaps a system assembled by yourself out of expensive components is going to be more efficient than the Reserator XT, but Zalman’s solution saves you the trouble of searching for components, assembling and fitting them together, digging for a lot of information, etc, to achieve the desired result. If you like the result, but not the process of achieving it, you may be interested in the stylish Zalman Reserator XT that takes a mere 10 minutes to get started and going.
My wish list: