by Cetera labs support account
03/24/2003 | 02:10 AM
It’s no secret that all contemporary components of the system case may generate a lot of heat and proper cooling is vitally important for the system to be in good health. Insufficient cooling may result in a physical damage of hardware caused by overheating.
Air cooling solutions are the most popular today. They are simple, low cost and quite reliable. Chips that require heat takeoff bear aluminum or copper heatsinks. Thanks to their large surface heatsinks dissipate the heat into the air quite effectively. Sometimes, it’s not enough, though. To improve heat dissipation, either the surface of the heatsink is enlarged or the air is directed along its ribs. As we can’t go the first way for long because the system case has limited dimensions, the second way became more popular. Everyone now knows what a cooler is: a device combining a heatsink and a fan, which is pumping air along the heatsink’s surface.
The most powerful heat generator among PC components is the processor. That’s why CPU cooling is so much spoken about and CPU coolers have become ever more expensive and sophisticated products. A good modern cooler that would guarantee effective heat dissipation even during extreme CPU overclocking usually has a copper heatsink weighing a few hundred grams and a powerful fan. But a good cooler is only half of the thing. It’s also necessary to create proper air in- and outtake in the chassis, otherwise the air will circulate through the fans heating up even more and reducing cooling effectiveness.
To avoid this undesirable effect the user has to install additional fans to suck the air in and blow it out, thus turning the system case into a kind of a desktop (or underdesk) wind tunnel. This tunnel will roar no less than a real one, believe me.
Powerful graphics cards also require active cooling, system chipsets don’t like overheating as well, a 7200rpm hard disk drive also generates a lot of heat… The number of fans in the chassis is growing and each fan contributes its tune to the overall chorus. What the poor user can do? If we disregard the possible compromises, there are two ways-out. First: to sacrifice high speeds for the sake of silence and “downgrade” to a VIA Epia system or something like that. The second way is to give up air cooling altogether and install a water cooling solution.
So, this is what the review is all about. Before we start we would like to thank ATACOM for the opportunity to test a PC2-C system from Koolance Company, which specializes in water cooling solutions. As every other Koolance creation, it has certain unique features, which we will try to reveal and discuss in detail in our review. We suggest starting with a discussion of the water cooling in general, and then we will pass over to all the pros and contras of the Koolance PC2-C system.
The concept of water cooling solutions is quite simple. For better and faster heat dissipation from the CPU we add one more link in the following chain: “die -> heatsink -> air”. It’s water. Overall, such a gadget is a closed circle with water pumped along it.
Water is driven through the system by means of a water pump. Water takes heat from the CPU, comes into the heatsink and transfers the heat to the air blown through the heatsink by fans. Then it cools down to room temperature.
Using water as a heat conductor allows us to dissipate heat into the air not at once but wherever we think it proper (not necessarily inside the PC case). Water is running through the pipes and they can be of any reasonable length. The same refers to the heatsinks, which can be made of any size (within reasonable limits of course). Water heatsinks are usually much larger than those used in CPU coolers. You just can’t make a CPU cooler very large because of dimensional and weight limitations. One more advantage of a water heatsink is its thin walls and large surface area. It means you don’t need to blow the air through it with the same strength as in CPU coolers, thus there is no need to install powerful and noisy fans.
Talking about CPU coolers, we should mention water units that now stand instead of them. Water units may greatly differ in their construction, so that you could write the whole treatise on them. Anyway, they all serve one purpose: to effectively transfer heat from the die to the circulating water.
The most popular water unit design: a copper or aluminum cylinder or brick as small as a CPU socket or slightly bigger with a drilled zigzagging or spiral channel for water. The channel starts and ends with nipples to connect pipes. That’s what a typical water unit looks like from the inside:
Water units can’t boast standardized retention mechanisms as coolers do. There is a whole lot of bracers, cramps, clams and the like, so water unit installation may prove either a very easy or awfully daunting task.
Enough for CPUs. There are other things in the system chassis that require active cooling, too. Take the North Bridge of the chipset, for example. They usually equip chipset North Bridge with a small cooler or a passive heatsink, which should be cooled down with the air from the CPU cooler. But as the CPU now features a water unit, the chipset heatsink gasps for air and the chip starts to suffer from overheating. It’s all right with an active chipset cooler, but a thing like that would be noisy… What shall we do? A water cooling system can take care of this heat source, you only have to include one more water unit into the cycle. For example, like that:
But the above construction has some bottlenecks. It requires a T-bend pipe in places where the two water streams join together and come apart. This would mean extra costs, extra junctions, and reduced reliability. That’s why sequential water unit connection is often used. In that case, the water would have a little higher temperature after coming through each water unit, but this shouldn’t affect the cooling efficiency at all. Our Koolance system features this particular connection scheme of water units. It has four units in total: for the CPU, chipset North Bridge, graphics chip and HDD:
Let’s take a closer look at Koolance water cooling system. We will certainly begin with the above mentioned water units…
The CPU water unit from the Koolance set is rather an unusual thing. It’s not a standard aluminum or copper “brick”, but something more interesting:
It consists of two hermetically jointed parts: the aluminum base and plastic case:
The base has a square thick foot in its center, exactly where it contacts the CPU die.
The water unit is a high quality product. Look at the CPU-contact pad: it’s actually shining mirror-polished:
Next to this spot, there is a groove for the thermal diode of the Koolance system. The system work mode is chosen basing on the measurements provided by the thermal diode. It doesn’t stand close to the CPU core, but rather to the side and thus takes not CPU, but water temperature:
The water stream is running between the other surface of the heatsink base and the case. The surface of the brick is not smooth under the case, but corrugated. This enlarges the surface washed by the water and creates small grooves where the water runs faster than between two flat surfaces:
The larger surface and faster stream are also the standard measures aimed at increasing the efficiency of an air cooler. But the water unit is almost the same heatsink, with that only difference that it dissipates the heat into water, not into air. The water unit developers claim that their solution can handle CPUs with up to 200W heat dissipation. That’s for real overclockers, no doubt!
The fastening mechanism of the unit deserves a separate mention. It consists of a central part and two bracer sets intended for Socket 478 and Socket A:
One set is for Athlon CPUs:
The other is for Pentium 4:
It’s very easy to install the water unit: just turn up the screw. You will never run a risk of crushing the processor die as there is a tight plate in the cap of the screw, which doesn’t let the screw go on any further when the pressure is too high:
The only thing we didn’t like about this water unit was the connecting pipes. They are plastic and look rather fragile. Koolance recommends using pliers to fasten clamps around the pipes, but warns against too much pressure. We didn’t take the risk and gave up those clamps altogether. There were no problems anyway; the pipes held on quite well:
When installed, the water unit looks like that:
The chipset heats up less than the CPU, to put it mildly, so the developers decided to relax a bit when working on the chipset water unit. Unlike the first unit, this device can’t boast any exceptional features:
It’s a small aluminum brick with three holes. Pipes are connected and everything is glued over. The water runs along the simplest trajectory in this brick: along a U-shaped channel. We can’t say it’s the most effective cooling solution, but the chipset simply doesn’t require anything more powerful. The retention mechanism for this water unit is a great example of simplicity and universality:
This water unit can be installed onto any mainboard instead of the standard heatsink or chipset cooler. The brace fits for most mainboards with different spacing between the fastening holes, but if the holes are placed too far apart, you can use special insertions:
The connecting pipes of the chipset water unit are made of aluminum, not of fragile plastic. But the glue they sit on might be the weak spot. To our surprise, it was very hard and you can’t possibly make it crumble :).
The snapshot shows the installed chipset water unit:
This water unit resembles the chipset one. The connecting pipes only come out straight, not in a curve:
We didn’t dare to install this water unit on a card with a powerful RADEON 9700 PRO chip and the like, as it doesn’t seem to be a record-breaking cooling solution. But it should be quite enough for chips like NVIDIA GeForce4 Ti or slower.
This water unit is fastened just like the chipset one. It can be installed onto any graphics card that has mounting holes for coolers:
The HDD water unit is an aluminum plate, about 1cm thick. There is a U-shaped channel inside for the water flow. You can get the way it was made if you look at the glued holes in the unit:
The HDD water unit is screwed to the hard drive at the side of the HDD PCB. When fastening the cooler, you should also use special thermal interface improving the heat dissipation:
You conscientiously mix the two substances and apply a layer of the obtained paste to the hard disk drive PCB. Then you press the water unit to the HDD and fasten it up with screws.
In a few hours the paste will turn into a rubber pad that fits close to all HDD components and transfers the heat to the water unit. This water unit can also be used with two HDDs simultaneously: you will only need an extra duo-bag of the thermal paste components and after applying the paste you will have to fasten the second drives to the other side of the water unit.
When installed onto one HDD, the water unit looks like that:
Koolance used submerged water pumps. It means they don’t have connecting pipes, but are completely underwater. The hermetically closed water tank is installed at the bottom of the PC chassis:
Tank volume is about half a liter. There are two sequentially connected pumps in it: one is taking water out of the system into the tank and the other is pumping the water from the tank into the system. It’s hard to say why Koolance engineers preferred to use two pumps instead of one more powerful pump. Maybe they got attracted by the noiseless operation of these two pumps, which work absolutely quietly, you only feel a slight vibration. Moreover, the dual-pump variant is more reliable. If one of them goes down, the other would still go on pumping and saving the CPU from overheating. There is a label on the tank with a scale to control water amount. The tank has a hole at the bottom for water refill and unloading:
The system is absolutely hermetic, so you can transport it in any position. Although you’d better set the system vertically when working :).
There are no surprises here: an ordinary air heatsink is used in Koolance system to cool the water:
The heatsink, fans, control panel and system PSU are all placed in a compartment that occupies the entire upper part of the chassis. One 5-inch CD-ROM drive bay was even sacrificed for it:
This compartment has no communication with the rest of the chassis, but goes out at the top of the system case:
Four standard 80mm fans are blowing air through this heatsink. Two of them are sucking the air in – they are both placed at the upper panel of the system case. The other two are blowing the air outside – one is at the upper panel and the other is placed at the PSU. We should note that all these blowing things produce quite a perceptible noise even in the “silent” mode. We might have been unlucky to have a chassis with poor fans, but still it was a sad thing to mention. After we replaced the default fans with the 80mm fans from Thermaltake, the noise was practically eliminated.
All “intelligent” parts of the system belong to the control panel. Everything is connected to it: fans, a thermal diode, pumps, indicators panel and even the system power circuit. The panel receives power from the PSU via an ordinary four-pin connector.
You can connect up to four fans to the control panel PCB and their voltages will be adjusted depending on the temperature. However, the system uses only three fan connectors, so you can plug in an additional fan there. For example, you may wish to install a fan at the back panel of the system case. This may become necessary, as there are no fans inside the system left, while there are still some components that might require additional cooling.
Unlike many other water cooling solutions, the creation from Koolance is not just a heap of pipes, pumps, water units and heatsinks. It is a live creature! And even shows some signs of intelligence :).
Firstly, the system starts up and shuts down together with the computer, as the control panel receives power from the computer PSU. So, you don’t have to turn on the water cooling pump manually, and hence there is no risk that you may forget about it :).
Secondly, in case of emergency (that is, during overheating), the control panel turns off the PSU of the system. It is possible due to the fact that the power-on button is connected not to the mainboard directly, but via the control panel of the water cooling system. Temperature is taken from the thermal diode on the CPU water unit. When the water temperature rises above 50oC, a warning sound signal is emitted. If during the next 30 seconds the temperature doesn’t decrease below the dangerous value, the system shuts down.
Thirdly, the system can work in three modes: “silent”, “adaptive” and “maximum” that differ in rotation speeds of the cooling fans. The following diagram shows the dependence of rotation speeds on the temperatures taken from the thermal diode:
In the “silent” mode, the fans receive lower voltage. In this mode the water cooling system produces less noise, but works less efficiently. This can lead to temperature growth in games or other applications, where the CPU and the graphics chip are highly loaded. In order for the water temperature not to notch the critical 50oC point, the fans are turned to their maximum when the temperature comes close to 45oC. When the temperature is again below 45oC, the system once again reduces fan voltages. This mode is supposed to suit for work in office applications, Web-surfing and similar “light” tasks. But in fact, we couldn’t make the system speed up the fans even running Unreal Tournament 2003 for half a day: the “silent” mode coped with this workload without any problems.
In the “adaptive” mode the voltages are smoothly increased according to the temperature. Below the 40oC point, the system works in the “silent” mode. After the temperature grows above 40oC, the fan voltages are raised which certainly improves the cooling efficiency. This mode suits for those users who regularly load the CPU with intensive calculations. Ideally, the system in this mode keeps the water temperature at a certain in-between value; fan rotation speeds are higher than in “silent” mode, but lower than in the “maximum” mode.
The last, but not least, “maximum” mode is for people who don’t care about silence and for extreme overclockers. When you turn this mode on, the fans receive full load of voltage, the system is roaring as a pregnant crocodile and the CPU feels freezingly cold :).
But back to our intellectual friend: the control panel PCB. What else did we find there? A warning sound emitter, a pair of transistors, and a pretty large transformer. Why are they here? The pumps installed in the water tank are powered from an AC source. And the transformer with a few transistors is none other but a classical converter of 12V DC into 220V (110V) AC. Thus, Koolance engineers solved the problem of the system autonomy: the pumps don’t require additional power from any external sources. They work only when the rest of the computer system works. As a result, the control panel consumes considerable amount of 12V power. In fact, this is one more drawback: the system comes without a PSU and if you install a low-quality one, it won’t cope with such high workload.
At the front side of the “fan & grid” part of the case, there is a temperature indicator, two LEDs and two control buttons:
Water temperature indicator is made of LEDs, and not of the weakly shining liquid crystals. So it is very bright in the night and daytime, and can show the temperature in either degrees Centigrade or Fahrenheit. Temperature indication mode is set with a button. Another button sets the work mode of the system: one press – “silent”, once more press – “adaptive”, one more – “maximum” and so on in a cycle… One of the LEDs shows that system is alive and working, the second one indicates if the fan rotation speed is forced. Overall, the control and indication are quite simple and understandable. Now let’s pass over to water exercises.
It’s no hard job to put this system together, but you will certainly need such overclocker’s qualities as patience and perseverance. The water hose doesn’t come cut into multiple pieces of required length, but is supplied as a water hose coil of a considerable length, which ensures some reserve in case you cut it wrong. To avoid such mistakes, you should install the water units and pipes after you put all the components in their proper places. Then it’s easy to determine the length of each pipe segment.
After you cut the hose into pieces, you can start putting together the water contour. The pipe between the tank with pumps and the heatsink is already in place, you only need to connect the four water units. To fasten the hose at the connecting pipes, you should use some tricky clamps: basically, you don’t screw, but wring them out with pliers or some similar tool:
We applied those clamps to all hose coupling with water units, except the CPU water unit. As we have said, the pipes of this unit look too fragile, and, moreover, the pipes are wide and the hose holds on very tightly even without clamps. We connected the water units in the following order: CPU - chipset - GPU - HDD. The resulting system is shown on the picture below:
We only have to add some water now. The filling hole is located at the bottom of the case and is closed with a screw-top. Koolance warns that you should use only distilled water in the system. However, I didn’t feel like running around the district in the middle of the night looking for distilled water and took the risk of using some purified drinking water from the bottle instead. The system took in about half a liter. Following the manual, we also added some ethylene glycol from the small bottle that comes with the system:
After I turned the system on, I heard a clear babbling sound produced by the air coming along the pipes and some really annoying noise generated by the pumps. I was about to get utterly disappointed: where was the promised silence? But it turned out that air bubbles didn’t let the system take enough water. After the pumps started working, the water level in the tank dropped. The in-taking pump started mixing air and water producing those horrifying sounds. I simply added water up to the specified mark on the tank, and the noise disappeared immediately.
Well now, the system is assembled and ready to work. Let’s test it.
We used the following testbed:
The test was carried out in Windows XP. We started the system and left it idle for two hours to check the temperature in the “idle” mode. Then we ran a deathmatch with bots in Unreal Tournament 2003 for two hours, too. That was the temperature value in the “burn” mode. Water temperature measurements were taken by means of the thermal diode included into the Koolance system. Air temperature was 20 oC during the test; the water cooling system was set to the “silent” mode. Here are the results:
First of all, we enjoyed the “thoroughness” of the system. When you buy PC2-C, you get everything necessary to assemble a water-cooled PC: the chassis and full-fledged water cooling solution. The water cooling system includes four water units to cool the hottest spots of the PC.
Secondly, the mounting of the water units and the entire system assembly are very easy. It won’t take too much time to create a complete PC in PC2-C case and, the most important thing is that you are very unlikely to experience any difficulties during system building.
In its “silent” mode, the system produces no loud noises (it will be even quieter, if you replace the 80mm fans with something better), providing excellent cooling at the same time. Overclockers like it, when it is cool and quiet :).
Although there are two pumps in the system, they don’t hum at all. Moreover, such solution provides better reliability: if one pump goes down, the other will continue upholding the system.
One more thing to mention is the light weight of the water cooling system itself. It’s absolutely hermetic, and can be easily transported without unloading the water. By the way, the added ethylene glycol allows using PC2-C in case the environment temperature is about 0oC or even a little below that and you shouldn’t be afraid that the water freezes up and burst the water units apart :).
First of all, there is no power supply unit coming with the system, although there is a chassis. (Koolance modifies third-party chassis and installs its water cooling solution there). Why didn’t they put a quality PSU and set a little higher price?
Second thing to mention is a not very high quality of chipset and graphics chip water units. While the chipset unit copes well with its job, the graphics chip unit won’t handle such monsters as ATI RADEON 9700 or NVIDIA GeForce FX.
The last issue to be discussed here is exactly the case when an advantage may turn into a bottleneck in no time. It is all about the rest of the system components. You see, the CPU, chipset, graphics chip and HDD are now equipped with water units, while the PSU, heatsink and fans are separated from the rest of the chassis in their own special compartment. So, there is no air stirring inside the system case at all. This may lead to overheating of voltage regulators on the mainboard or graphics card (they are usually cooled by the air from neighboring coolers). If you have a CD/DVD-RW, which produces quite a lot of heat at work, the situation may become dangerous. You can install an additional 80mm fan onto the back panel of the chassis to have some airflow in the system case. There is enough room to put this fan on, but PC2-C comes without it. They seem to be really stingy, aren’t they? :(