Zalman Reserator 1 Plus Liquid Cooling System Review

We would like to introduce to you a water cooling system from Zalman – The new modification of their exclusive Reserator solution: Reserator 1 Plus. Let’s find out what the innovative peculiarities of this model are and how much more efficient the improved connecting pipes design, new CPU water unit and new GPU water block can make this system.

by Anna Filatova
09/29/2005 | 09:22 PM

Each overclocker knows what water-cooling systems are and why they are better than standard air cooling solutions. To cut the long story short, water cooling systems help a lot during extreme overclocking experiments and allow to get rid of the annoying cooler fans noise. The quietest water cooling systems are those designed without any fans at all, and when users ask me if that is possible, I usually say yes, sometimes. Take for instance Zalman Reserator 1. This water cooling system generates no noise, it has no fans on the heatsink. Moreover, the heatsink is combined with the cooling liquid reservoir and also contains a pump inside.


We have already reviewed Zalman Reserator 1 in the article called Aesthetic Water Cooling Solutions: Zalman Reserator 1, ZM-WB2 Gold and ZM-GWB1, so you can check it out for details.

Not so long ago Zalman released a modification of their Reserator system aka Zalman Reserator 1 Plus, and we couldn’t wait to get into our lab for testing.

Zalman Reserator 1 Plus: What’s New?

The cooling system arrived in our lab in a huge box, big enough for a large reservoir-radiator:

The box is shorter than that of the older Reserator system, but much taller, because there are more components inside the package.

The standard Zalman Reserator 1 package included just a CPU water unit with the retention mechanism, radiator unit with a pump, silicone tube, flow indicator, user’s manual and a set of clamps and connecting pipes for the tubes.

The accessories included with the new Reserator 1 Plus are a way more interesting:

First, the cooling system is bundled with a water unit for the GPU and heatsinks for the graphics memory chips. All these items together with the corresponding retention components are packed into individual plastic box. Second, there is a new CPU water unit, which is also packed separately, together with all the necessary clamps and screws. Third, there is a bottle with special liquid chemical additives that you should add to the water to prevent internal corrosion of the metal parts and mold in the tubes.

Finally, the radiator-reservoir looks different from what it used to look like in Reserator 1. It is of the same shape, but has become of radical black color:

As you can see from the photo above, the Reserator connecting pipe have been modified, too:

If you press against these gray locks, the connecting pipes can be easily put on or taken off together with the tubes. Of course, these new connecting pipes are included into the package accessories. As you remember, the old Reserator 1 modification had threaded retention for the tubes, which was not the most convenient thing, I should say:

Have the technical specifications of the pump and the radiator itself changed? Nope, they are exactly the same. Take a look yourself. There are two snapshots of the spec marking on the Zalman Reserator 1 and Reserator 1 Plus:

You can also compare the inscription on the reservoir lids:

As you see, the pump and the Reserator of the Zalman water cooling system remained the same. The same 6.5kg of aluminum, the same capacity of 2.5 l of water, the same modestly powerful noiseless pump and huge cooling surface of the Reserator unit.

The tube included with the new Zalman Reserator 1 Plus is also the same silicone tube that we have already seen before. And just like before you get one long tube and can cut it the way you need for your particular system.

What has been changed dramatically, however, is the component water units. And this is going to be the most interesting part of our review today. Let me start with the CPU water unit.

ZM-WB3 GOLD CPU Water Unit

The CPU water unit, Zalman ZM-WB3 GOLD, is packed into a transparent plastic box and can be sold separately as an individual product. This is no longer a boring white paper box we got with the Reserator 1 back in the days:

The CPU water block package includes two connecting pipes and two clamps for the tubes, different retention sets for mainboards, hermetic pads for the screws, user’s manual and a tube of brand name thermal paste:

The retention mechanism is fairly simple. It consists of a few different frames, couple of stands and a resilient clamp with interchangeable grips for the screws. So, you can easily install this water block on any contemporary processor. It is fit for Intel Socket 478/775 and AMD Socket 462/754/939/940.

The size of the new CPU water unit is much smaller than that of the old one. It remained of the same diameter but is twice as short:

The connecting pipes for the tubes are now designed to be wrenched on, however, overclocker’s strong fingers would be more than enough so you can easily do it without any special tools. However, if you don’t like the idea of fastening the tubes with the screws (that is when you have to deal with twisted tubes afterwards), you may as well use connecting pipes of different design that also come with the CPU water unit. In this case you will need to fasten the tubes with the clamps.

The bottom of the water unit that gets pressed against the CPU remained as perfect as it used to be: they managed to polish it off chemically to mirror-shine:

You can see four screws on the photo that hold together the new CPU water block. Yes! They have finally made it possible to look inside this part of our water cooling system:

The water unit consists of a copper footing with ribbed grid in the center, so that the water flow is directed to go along the ribs, and an aluminum lid with threaded holes for the connecting pipes. The rubber gasket sits in a round groove of the footing thus ensuring proper impermeability. When the water unit is assembled, the gasket is so tightly pressed against the flat surface of the lid that the whole construction is 100% secure. The remarkable thing is that even though this gasket is squeezed hard when you tighten the screws, it prevent s the two parts of the unit from touching one another. And since there is no contact between aluminum and copper washed by the water of the cooling system, the CPU unit turns even more robust against corrosion.

The inside design of the water unit shows that it is not very flow-resistant that is why it goes well with the pump of the Reserator.

Well, as for the efficiency of the new CPU unit, we will check it out during our tests, and in the meanwhile let me tell you a little bit more about another innovation we discovered in the Reserator 1 Plus package.

ZM-GWB2 GPU Water Unit

Those of you who remember the old Zalman water units for graphics processors, will certainly understand that the new GPU block design is not another way of ripping off the users, but a necessity.

The new GPU unit can also be sold as an independent product from Zalman:

The package contains the GPU water unit itself, graphics memory heatsinks, a resilient clamp, some stands, screws, plastic pads to go under the screws, tube clamps, user’s manual and an irreplaceable tube of Zalman’s brand name thermal paste:

The resilient clamp with twi pairs of fastening holes is intended to fit for any graphics cards from the ATI RADEON 9***/X*** and NVIDIA GeForce 4 MX / GeForce FX / GeForce 6 families, up to RADEON X850 XT and GeForce 6800 Ultra Extreme. Yes, this is no mistake, now the company is so confident about the quality of their water unit that they allow installing it even on the hottest of the contemporary graphics cards:

GeForce 7800 GTX and ATI R520 do not count, because the former is cooler than GeForce 6800 Ultra, and the latter hasn’t been announced yet.

The new GPU water unit can also be taken apart, just like the CPU unit, we have just discussed. So, let’s see what it looks like inside:

The idea is the same as by the CPU block: a footing with s grid, a lid and rubber gasket. This time, however, both parts of the unit are made of aluminum and the lid doesn’t participate in directing the water flow. In the CPU unit the lid gets so close to the top of the ribs inside that the water has to flow through the ribs. Here the grid is only ј above the bottom of the footing. The contact surface of the GPU unit is not mirror polished, you can clearly see the machining tracks on it:

You can see from the picture that the contact surface is slightly sticking out above the rest of the unit. This way the GPU unit will not end up sitting on the protective frame instead of the actual graphics processor die by some graphics processors.

Again, as far as the efficiency of the new GPU unit is concerned, we will find it out in a little bit when we move on to the testing results.


Zalman worked real hard to make the assembly process as boring as possible: no unexpected difficulties, all water units fit perfectly in their designated spots, the tubes are easily cut and connected, water is poured inside and the whole thing gets powered up. After that you shut the whole thing down, disconnect the flow indicator and turn it the other way around to get it connected the right way. It takes the pump about 10 seconds of gurgling to remove all the air from the tubes and then dead silence sets in. Only the wobbling flow indicator tag shows that the system is actually on. The system is ready to undergo our tests. But before we start let me offer you a few step-by-step assembly pictures, to illustrate everything I have just said:

The CPU water unit has just been installed:

The GPU water unit has just been installed, too:

We didn’t install Zalman’s graphics memory heatsinks this time, because our GeForce 6800 GT allowed removing the GPU cooler without removing the original NVIDIA graphics memory cooler. The graphics card’s own graphics memory cooling solution with a heatpipe design seemed more efficient than simple heatsinks offered by Zalman. We made our choice:

The tubes were connected to the water units and were led outside the system case through the holes in s special back panel bracket. This bracket is supplied with the Reserator 1 Plus system in the same plastic bag with the replacement clamps and connecting pipes:

For our tests we assembled a really “hot” system with an overclocked CPU and a powerful graphics card.

Testbed and Methods

Our testbed was assembled in a closed case and included the following components:

The room temperature during our tests was around 24-25o C.

During our first testing round the Zalman Reserator 1 Plus was set at about 50cm to the right of the system case away from all air flows. In this case the Reserator works as a classical passive heatsink, so that its heat dissipation efficiency is strictly determined by the difference of the environment temperature and water temperature inside the Reserator.

However, there is a great way of increasing the efficiency of the Reserator cooling system without adding any additional noisy components to the system. All you need to do is place the Reserator behind the system case, right at the back panel, where the PSU and other fans (if there are any) oust the air from the system case. The thing is that the temperature of the airflow directed at the Reserator will be much lower than the temperature of the water inside it, because all the heat from the CPU and graphics processor are already taken by the water units, and the air inside the system case heats up just a tiny bit by the remaining system components.

So, for our second testing round we put the Reserator unit behind the system case at a 20cm distance from the panel, so that it could be in the way of the outgoing air flow generated by the 80mm fan of the PSU and a quiet 120mm rear case panel fan rotating at only 1,400-1,450rpm.

Thermal Performance

We will compare the thermal efficiency of our Zalman Reserator 1 Plus system with the results obtained in case of standard graphics card cooling and a Zalman CNPS7000B-Cu cooler working at its maximum speed. The tests were run in two work modes.

In Idle mode I was reading a novel from an on-line library in Internet Explorer for two hours. After two hours I took the temperatures of the processor (CPU), mainboard (MB), graphics processor (GPU) and graphics card (VIDEO). To make these measurements I used ASUS PC Probe and Riva Tuner utilities.

In UT2004 mode we were running Unreal Tournament 2004 Deathmatch DM-Deck 17 level with two players, eight bots, maximum graphics quality settings in the heaviest mode possible: 1600x1200 with 8x FSAA and 16x AF.

These test sessions were so long, not because I like to read or to play Unreal Tournament so much on a powerful system like that :) The thing is that the system takes so much water and is so huge that it needs at least an hour of non-stop operation for the water temperature to stop growing and remain stable at a certain level.

All results are summed up in a single diagram below. The results obtained with an air-cooling system are marked as “AIR”, and the results of Zalman Reserator 1 Plus system standing behind the system case in UT2004 mode are marked as “Reserator 1 Plus + FAN”:

The system CPU and GPU temperatures are lower than with air cooling in all test modes.

Despite its smaller size, the CPU water unit proved more efficient than the celebrity air-cooler from Zalman and copes easily with the Intel Prescott processor overclocked to 4GHz.

The GPU water unit didn’t impress us with any outstanding efficiency. The GPU was only 2o C cooler than in case of a standard cooling solution. So, I have to admit that this water unit will not suit for extreme overclocking of hot graphics cards.

“Free” air-cooling of the Reserator unit by the system case fans resulted in 8o C overall reduction of the water temperature.

So, let’s draw some conclusions now.


If we compare Zalman Reserator 1 Plus with any air cooling system or some traditional type of water cooling system with a fan on top of the heatsink, then the Zalman baby is undoubtedly better from the noise prospective. The totally silent cooling solution is always better than any whisperingly quiet fans.

As for the cooling efficiency, Zalman Reserator 1 Plus also did a great job in our test session. It managed to cope easily with an Intel Prescott processor overclocked to 4GHz and a powerful GeForce 6800 GT based graphics card. The temperatures of both: CPU and GPU were lower than in case we used a Zalman CNPS7000B-Cu working at full speed and a standard graphics card cooling system.

If we compare Zalman Reserator 1 Plus with the previous model, Zalman Reserator 1, the biggest difference will certainly be the use of new water units. The CPU water unit proved highly efficient. It is not only as good the old water unit modification, but it also better suits to withstand corrosion, is smaller, lighter and easier to mount.

The current water unit for the graphics processor is a way better than the “thing” they used to offer with the previous Reserator model. Although, there is still room for improvement. I believe that if they use copper footing and bigger ribbed grid inside the unit will make the device much more efficient. Nevertheless, even now this water unit guarantees lower GPU temperature than the standard graphics card cooling system.

Other innovations introduced in Zalman Reserator 1 Plus are not vital but pleasing: black color of the radiator, protective additives for the water solution, new connecting pipes for the tubes, special back panel bracket for the system case, etc.

All in all, the new Reserator 1 Plus has definitely turned out better than the previous model.