A Home-Grown Water Cooler for 115 Dollars
Редакция THG,  28 мая 2001


Water Cooling - Better than Any Air Cooler

Intro

An ideal combination of a heat sink and a fan produces impressive results, as we showed in our last comparative test "Can't Touch This: A Comparison of 46 CPU Coolers". The best model, the Swiftech MC462, which comes equipped with a solid copper heat sink, achieved a temperature of 30 degrees when used on an Athlon 1000! The majority of the coolers we tested lowered processor temperature down to 40 to 45 degrees, whereas the worst cooler only reached 56 degrees. Many readers dream of hooking up an effective and efficient water cooler to their system, only to be scared off by the complicated assembly and potential expenses.

But now - the moment you've all been waiting for - here's our own home-grown water cooling system, which can be integrated into any and every PC system and costs less than 155 dollars to boot! In order to test the best possible system, we spared neither expense nor effort for this construction.

Construction - Waterblock, Radiator, Pump, Hoses

We installed this water-cooling system into one of our existing PC systems. The computer was running on an AMD Athlon (Socket 462) that was supplied with an MSI board (AMD 760 chipset). Our water cooler consisted of three basic components - a water block, a radiator with two fans and a water pump. All three components were interconnected via transparent hoses, through which the water flows.

The principle behind a water cooler can be explained in a few words. The pump, which has a capacity of up to 5 liters per minute, forces the water through the entire cooling circuit. While in operation, the water block fills with water. The water absorbs thermal energy from the processor and heats up slightly. In the radiator, the water dissipates its higher thermal energy through the large surface area of the cooling fins into surrounding air. The fans attached to the radiator ensure that air circulates at a high rate. This means, of course, that the lowest CPU temperature the cooler can produce is essentially dependent on the ambient temperature. Our cooling system will never be able to produce a temperature lower than room temperature.

The advantages of our cooling system - the temperature remains virtually constant, no matter how much processor capacity has been taken up. This is not the case for a conventional cooling system - the temperatures that these cooling systems produce increase automatically with an increase of CPU utilization.

Construction - Waterblock, Radiator, Pump, Hoses
Basic set-up of the water cooler - set up outside the PC case.

Waterblock - The Real Cooler

In our set-up, the water block is where the cooling actually takes place. It transfers heat from the CPU to the water. The water circulates constantly at a high rate, which keeps the CPU temperature low, hence the cooling effect. In the following pictures, you can see how the water block was constructed and how it works.

Waterblock - The Real Cooler
All the separate parts that go into building a waterblock.

Waterblock - The Real Cooler
The waterblock has two inlets for the water hoses.

Waterblock - The Real Cooler
The hoses are attached using knurled screws.

Waterblock - The Real Cooler
Tightening the screws guarantees an absolutely watertight seal.

Waterblock - The Real Cooler
The waterblock without the cover. Once in operation, a large amount of water flows through these channels.

Radiator with Two Fans

The grunt work is done by our radiator, which - as the name implies - transfers the heat from one medium to another by radiation. Since heat always flows from a warm medium to a cool one (physicists, please forgive this mediocre formulation! Thomas Pabst/Editor in Chief), a radiator is designed so that the heat of the water is dissipated through the fins into the surrounding air. The fins ensure that the surface area is large, while the fans attached to the radiator keep the air stream constant. In the following pictures, you can see the radiator we installed in our cooling system.

Radiator with Two Fans
The radiator is a very important component in our cooling system. It is cooled by two powerful fans.

Radiator with Two Fans
The cooling fins dissipate the heat from the water into the surrounding air.

Radiator with Two Fans
Both hose inlets on the radiator.

Pump - 5 Liters of Water a Minute

To keep water flowing through the cooling system at a decent clip, you need a pump. In general, any aquarium pump will do, as long as its flow rate and electrical connections are adequate. We used a centrifugal pump with a maximum flow rate of 300 liters per hour (according to the manufacturer), which is actually more than sufficient. In reality, the flow rate ends up being lower, due to narrow hoses and adapter interference. However, this pump is more than sufficient to cool an AMD Athlon processor at a loss rate of up to 85 percent, depending on the version and clock speed. You could use the same set-up to cool an Intel Pentium III or an AMD K6-2 (Socket 7) effectively. The following pictures show the pump and its inlets from different angles. In addition, we've prepared a table with the pump specs.

Pump - 5 Liters of Water a Minute
This small aquarium pump suffices to keep the water circulating in a cooling circuit.

Pump - 5 Liters of Water a Minute
The inlet and the outlet have been fitted with hose adapters.

Pump - 5 Liters of Water a Minute
The adapters reduce the inlet diameter, which allow small hoses to be attached. The sealing rings prevent leakage.

Pump - 5 Liters of Water a Minute
The pump and adapters are ready to be hooked up.

Pump - 5 Liters of Water a Minute
The rear side of the pump without its plastic cover. Here you can see clearly that all the components are set in white plastic.

1046 Centrifugal Pump
Flow rate 300 l/h
Discharge head 1.20 mWs
Power consumption 5 W
Inlet for the hose Dia. 13 mm
Outlet for the hose Dia. 11 mm
Dimensions L x W x H mm 145 x 75 x 103

Step-by-step Instructions on Building a Water Cooler

These instructions for building a water cooler should be clear to any user who has a little experience in building PC systems.

Step-by-step Instructions on Building a Water Cooler
First, the conventional cooler and fan must be removed from the CPU, and the CPU itself must be cleaned.

Step-by-step Instructions on Building a Water Cooler
Afterwards, the CPU is returned to its mounting and covered with some thermal paste.


Step-by-step Instructions on Building a Water Cooler
Next, the pre-assembled waterblock has to be attached.


Step-by-step Instructions on Building a Water Cooler
The PC case needs to be accessible from all sides. Any extraenous or obstructive wires should be moved out of the way first.


Step-by-step Instructions on Building a Water Cooler
Be very careful when positioning the waterblock on the processor. Misplacing it quickly destroy your processor.


Step-by-step Instructions on Building a Water Cooler
Don't attach the clip until the waterblock has been put in its final position on the processor. The clip ensures that the waterblock remains firmly in contact with the processor.

Step-by-step Instructions on Building a Water Cooler
Avoid bending the hoses (as in the picture).

After the water block has been assembled, the lines must be attached to the remaining components.

Setting Up the Hoses and Wires

Now, the wires and hoses have to be set up for water and electricity. The following photos show how we placed the wires and hoses on our system.

Setting Up the Hoses and Wires
The hoses feeding into the radiator are threaded through an opening in the case.

Setting Up the Hoses and Wires
Hose inlet on the radiator.

Setting Up the Hoses and Wires
The hose must be placed very carefully if it is placed over sharp edges.

Setting Up the Hoses and Wires
Hoses inside a PC case.

Setting Up the Hoses and Wires
We put the radiator and fans of our water cooler on top of the case of our PC. However, the water cooler can also be set up to run inside a PC case.

One more thing about our rather stout radiator - since we chose to install our cooling system on a standard tower case, the radiator was too large to fit into the case along with the rest of our equipment. If you own a large tower case, you should be able to install the radiator inside the case, which makes the entire setup look a bit spiffier.

Test Run - Filling and Checking the Seal on the Cooling Circuit

It's all set up now, we're ready to roll - it's time to feed water into our cooling system. First, though, we have to fill a container with water and attach it to the inlet of the cooling system. There's nothing simpler than using normal tap water for this, as long as it isn't too hard. If your water is too hard, this can eventually produce furring in the cooling system. In order to make our cooler look more appealing, we dyed the water red with ink. This also makes it much easier to determine the flow rate. It is absolutely essential to ensure that your system is watertight before installing it in your PC. Any subsequent leakage while running the PC would cause a short, and thus ruin a lot of components.

Test Run - Filling and Checking the Seal on the Cooling Circuit
Once all the component groups of the water cooler have been installed, you can feed liquid (water) into the system.

Test Run - Filling and Checking the Seal on the Cooling Circuit
A water bottle acts as a cistern.

Test Run - Filling and Checking the Seal on the Cooling Circuit
The pump draws water through the radiator.

Test Run - Filling and Checking the Seal on the Cooling Circuit
The hoses are taped to protect them from being damaged by the sharp edges of the opening.

Test Run - Filling and Checking the Seal on the Cooling Circuit
The water cooler has been installed in our PC system and filled with liquid.

In order to ensure that the cooling system is perfectly watertight, the cooling circuit should be set up outside the PC system and allowed to run for a minimum of 12 hours.

Bleeding the Cooling Circuit

Once the cooling system has been entirely filled with water, the entire circuit has to be bled. The system will not cool properly if the air hasn't completely been removed from the system! This is true for all the components in the cooling circuit. The simplest way to bleed it is to run the pump for about an hour and thus allow all air bubbles to escape.

Bleeding the Cooling Circuit
Before the cooling system can function perfectly, the cooling circuit has to be bled. This can be accomplished by moving the radiator back and forth, allowing the air to escape to the water bottle.

Bleeding the Cooling Circuit
The majority of the air collects in the radiator, which can only work properly if there is no more air trapped in its cooling fins.

Overclocking: 30 Percent Increase in Clock Speed

The following chart shows examples of AMD processors that were hooked up to our water cooling system and overclocked. During the testing procedure, the temperature in the water block was a constant 24 degrees - the best cooler in our last comparative test (Can't Touch This! A Comparison of 46 Coolers) managed a mere 30 degrees. We used processors from 750 MHz to 1333 MHz, overclocking them by simply increasing the clock multiplier. Had we also increased the front side bus, the results would probably have been even better, but the system's stability would have begun to suffer after a brief while. One thing is quite clear - the AMD Duron 750 is the processor with the best overclocking rate. A 30 percent increase in clock speed is more than satisfactory - results like these are impossible when using a conventional cooling system with a cooler and fan.

We used Quake 3 Arena and SETI as benchmarks, although the latter program was only run to ensure that we used virtually 100% of CPU capacity. Every CPU we tested was run at full capacity for several hours, which means that the overclocking rates listed here refer to rates in a stable PC system.

normal overclock
CPU Type (AMD) CPU Takt in MHz FSB in MHz Multiplikator Core - Spannung in Volt FSB in MHz Multiplikator Core - Spannung in Volt CPU Takt in MHz
Athlon 1333 133 10 1.700 133 11.5 1.850 1533
Athlon 1300 100 13 1.700 100 15 1.800 1500
Athlon 1200 133 9 1.700 133 10.5 1.800 1400
Athlon 1000 100 10 1.700 100 12.5 1.800 1250
Duron 900 100 9 1.600 100 11.5 1.850 1150
Duron 750 100 7.5 1.600 100 10.5 1.850 1050

Overclocking: 30 Percent Increase in Clock Speed

Overclocking: 30 Percent Increase in Clock Speed

Overclocking: 30 Percent Increase in Clock Speed

These charts clearly demonstrate that AMD processors that are factory-set to run faster hit the limits of their clock speed more rapidly than their slower siblings do - despite our effective water cooler.

Pros and Cons of Water Coolers

The bottom line in a comparison of water-cooling and conventional air-cooling is obvious - water cools much better and can serve up a substantially lower noise level. Not only that, but processor temperature is guaranteed to remain low even when processor capacity has been maxed out. Since the processor transfers its heat to the cooling water, the temperature in the PC case is automatically lower. It removes the need of additional case fans and therefore reduces noise. Hard-core overclockers will be able to reach record clock speeds using a water-cooling system. Although the price tag might be higher than for a good conventional cooler, a water cooler is more durable.

Nevertheless, we still don't want to gloss over the cons of using a water cooler - in the event of a leakage, expensive components in a PC system can be destroyed in no time.

Prices for all the Components

Our cooling circuit was assembled using standard components. All the parts - with the exception of the radiator - are available in a hardware store, a pet store, or in an electronics hobby store. Our pump cost 34 dollars, although there are models that are considerably cheaper and less powerful that will still do the job. Acceptable pumps cost approx. 12 dollars and have an throughput of between 150 and 200 liters per hour. The most expensive component is no doubt the radiator. In our case, it cost 65 dollars to buy the version with two fans. The hoses can be purchased in any pet store and vary in price between 1 and 2 dollars per meter, depending on the thickness and the strength you require. Installing 2 meters of hose in our system cost us a total of 5 dollars.

Acquiring the waterblock is not exactly what you would call cheap. Although this component is available in Taiwan for what amounts to 30 dollars (from, for example, http://www.senfu.com.tw/English%20homepage/link.htm). It's a lot less pricey to buy a complete kit, which often is an unfortunate compromise between product quality and price. No matter what, you have to be hard-nosed and negotiate a good price if you want to get an inexpensive cooling system. Otherwise, it's not that bad an idea to improvise and assembly your own system.

Some hardware stores offer hoses and pumps for a song, which can then be installed in a cooling system. The total bill for the cooling systems shouldn't be more than 115 dollars.

Conclusion - Water Coolers Beat All Conventional Coolers

The cooling system we built ourselves was able to maintain a constant temperature of 24 °C. The best cooler from out last comparative test - the Swiftech 462 - (A Comparison of 46 Coolers) - managed to reach a temperature of 30 °C. This chart shows the speeds of the AMD Athlon processors that we overclocked in the laboratory. Overclocking rates were the best for the AMD Duron 750 out of all the AMD processors - a whopping 30 percent increase when using a water cooler. Results like these are impossible if you use either an el cheapo standard cooler or a powerful conventional cooler.

The Duron 750 operated completely stable at 1050 MHz. In terms of percentages, Athlon clock speeds of 1200, 1300, and 1333 MHz don't lend themselves as well to overclocking, as you can see in our charts.

We also tested our cooling system on the 1400 MHz AMD Athlon, which will be introduced in a few days. However, we didn't include these results in our charts. -Finally, the components we used in our cooling system cost a total of about 115 to 135 dollars. Overclocking aficionados shouldn't pinch any pennies, taking great care when selecting their components.

This, however, is not the last word on cooling systems - in our next article, we will present a souped-up version of our water cooler that achieves considerably better results, for almost the exact same price.

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