Build a liquid cooled PC
I have previously written tutorials on how to build a silent workstation and a file server. Those two systems can be used as templates for other, similar computers. You can easily swap components around, and, as long as you conform to compatibility guidelines, you should be able to put together a nice desktop PC or server. This time, I have written a brief build log of a water cooled PC.
What is a liquid cooled PC?
The vast majority of personal computers, workstations, and servers are air cooled. Air cooling simply means that every heat producing component is cooled by means of a heatsink and/or a fan. Thus, in a typical high-end system, you might find at least two large heatsinks (one for the CPU and one for the GPU) and several spinning fans. Fast chips usually produce a lot of heat, so the more powerful the system is, the more cooling it requires.
However, air is not the most efficient cooling medium. A lot of industrial machines and vehicles are liquid cooled because only liquid coolants provide the required thermal performance. Computer builders have implemented Liquid cooling as well, primarily because has more thermal headroom than air cooling, thus making it ideal for cooling overclocked computers.
Who needs water cooling?
If you are happy with the amount of processing power of the workstation we built earlier, then your probably do not need to worry about water cooling. However, if you require even more power, or if you are interested in a further challenge in your PC building hobby, then you might consider giving water cooling a try. Furthermore, liquid cooling may be the only viable option for those of us who live in hot and humid environments where air cooling struggles to keep the machines within recommended thermal parameters.
Water cooling takes quite a bit more planning than air cooling. Water cooled components are relatively less standardized and far less ubiquitous. Thus, you are going to have to do a lot of research and be prepared to make a few necessary modifications to your hardware. The first thing we are going to do is decide on which components are going to be water cooled. The simplest water cooling system will cool the CPU only. More advanced rigs might additionally include the video card (or multiple GPUs), RAM, the motherboard, and hard drives. In the present series, I am going to water cool the CPU and the GPU, as they are the two hottest components in a high-end PC.
Picking the right chassis is crucial. There is an inherent difficulty in choosing a chassis because very few PC cases on the market offer support for water cooling. Yes, most manufacturers clam to support water cooling but the support is usually limited to two holes in the back of the case for routing water cooling tubes from an external cooling rig. While this type of setup might work for some users, I believe that it is much more functional (and elegant) to have a self-contained water cooled system, whereby all the electronic and thermal components are housed inside the computer chassis. Some of the high-end full tower cases, such as Corsair 800D, support top-mounted radiators, but most smaller cases do not come with radiator mounting options. Therefore, if one wants a reasonably small system, one needs to make modifications to a medium tower chassis in order to accommodate all the required components.
For the purposes of this build, I have chosen the Lian Li PC-05NB mid-tower chassis (Figure 1). The chassis is actually rather small, though it does support full-size ATX motherboards. I happen to really like the case. It is very elegant, understated, and perfectly functional. Most importantly, it features a reversed ATX layout, whereby the motherboard is mounted upside-down. This facilitates the installation of a radiator in the roof, especially when a mATX motherboard is used. Indeed, there is plenty of room to mount a 360 mm long and 50 mm thick radiator in the removable roof without blocking access to other components.
Figure 1. Lian Li PC-05NB mid-tower chassis
Modifications to the case
In order to mount the radiator, an opening had to be cut in the roof of the case. Because the roof is removable, the required modification was rather simple. To mount the radiator, I used a Bitspower radiator grill (Figure 2). I recommend using a radiator grill rather than mounting the radiator directly to the case. The Bitspower grill is of excellent quality, comes with the necessary mounting hardware, and matches the beautiful finish of the case perfectly. In fact, when installed, it looks as though it belongs there, by design. Additionally, because I prefer the look of a black interior, I had the internals powder coated in satin black finish. It is, of course, not required, but it does, in my opinion, improves the look of the kit.
The modification was made by Bill Owen at MNPCTech. Bill is a master modder, and I am fortunate that he lives nearby. He did a beautiful job mounting the radiator.
Figure 2. Bitspower radiator grill
Having mounted the radiator in the roof, there is just enough room left inside the chassis for a micro-ATX motherboard. I believe a full-size motherboard would have fit, as well, but access to the topmost headers would have been difficult. Because I wanted an AMD-based system, I chose the Asus M5A88-M motherboard for this build. It is a really decent and affordable motherboard, with just enough stability, speed, and overclocking functionality to meet my current needs.
At the time of writing this article, the new AMD Bulldozer processors became available, so I took advantage of the recent price drop on the AMD Phenom line and picked up the top-of-the-line Phenom X6 1100T. It is a fast, modern CPU with six physical cores and good overclocking capability. No, it is probably not as fast as the Core i7 chips but I had already built an Intel-based system for my workstation, so this time, I wanted to try AMD. Besides, AMD systems are still quite a bit less expensive than their Intel equivalent.
I chose the same RAM as for my workstation, the Kingston Hyper-X, in blue, to match the overall color scheme of the build (black-blue-white). So far, I've installed 8 GM of RAM, but there are two more slots left for an additional 8 GB, should the need arise.
I could not imagine a modern system without an SSD. They have come down in price sufficiently to justify the purchase. I chose the OCZ Vertex 2, the same as in my workstation. Yes, I realize there are faster SSDs available, but I have had a really good experience with Vertex 2, and, frankly, I was a little hesitant to choose the latest Sandforce-based model due to the unusually high number of negative reviews and a rather mixed user experience.
Before you even begin working with water cooling components, I recommend that you bench test the setup. It is essential to make sure that the system works perfectly at this stage. Should you run into any issues with the hardware, be sure to work them out. I also installed the operating system while the hardware was still on my bench (Figure 3). Once inside the OS, you can use a few different free applications to further test your hardware/software configurations. In my case, I discovered two incompatibilities with the Gigabyte motherboard, so I replaced it with an Asus board. Once all the issues were eliminated, I moved on to building the liquid cooling loop.
Figure 3. Testing the system on my bench.
Water cooling components
The real challenge and fun of putting this system together involved the water cooling components. There are several excellent guides to building water cooled systems on the Internet, so I will limit the present discussion to the components I chose for the build. The parts I picked are fairly common and so my setup should be generalizable.
The radiator is the primary heat exchanger of the system. Its overall surface area determines its cooling capacity: the larger, the better. Due to the physical limitations of my chassis, I was only able to accommodate a 360 mm radiator. It should be sufficient for cooling two components - the CPU and the GPU. For additional components, say for an extra video card, a larger radiator would be required. Because I am less concerned with absolute cooling performance and more concerned with quiet operation, I chose a radiator with a relatively low, 10 fins-per-inch count (FPI), specially designed for low-RPM, quiet fans.
I chose the EK-CoolStream-RAD XT, 360 x 54 mm radiator. It is the maximum thickness to fit in my case without having to make any further modifications. It takes up one 5.25-inch bay, thus leaving the other available for a DVD or Blue-Ray player. In installed an MNPCTech acrylic radiator grill on the bottom of the radiator, mainly to protect the delicate fins from accidental damage (Figure 4).
Figure 4. The EK radiator with an MNPCTech acrylic grill mounted
I chose three Scythe fans to mount on the radiator. I have been using Scythe fans for quite some time and have never had a problem. They are known for being quiet and reliable. I set the fans up in the so-called "pull" configuration. The fans are positioned between the radiator and the Bitspower grill, pulling hot air out of the case. It is a fairly common type of setup, characterized by good cooling performance and relatively quiet operation.
Most water cooling systems require a reservoir to hold the cooling fluid. There are a few different types of reservoirs available. I considered a 5.25-inch bay-mounted reservoir, but I didn't have enough space available, so I chose a stand-alone reservoir, the XSPC acrylic reservoir (Figure 5). It is a very decent reservoir with the ability to be mounted directly on top of a Laing DDC (or equivalent) pump.
This reservoir-pump combination works really well and helps save the precious space inside the computer case. The reservoir has an inlet and fill port in the top, which works perfectly for the purposes of my build.
Figure 5. The XSPC reservoir inside the case
As mentioned earlier, my reservoir can be mounted directly on top of a Laing DDC pump. Laing DDC is one of the two popular types of water cooling pumps. It is sold under different names by different manufacturers, but it is, essentially, the same (or very similar) pump. It comes with a Molex power connector and a 3-pin connector for the tachometer, so that the pump's rotational speed can be monitored, if connected directly to the motherboard. The pump is both powerful and quiet enough for my needs. Yes, there are probably pumps that are quieter but my choice was also determined by the fact that that I really wanted the pump to be mounted directly onto the reservoir.
The reservoir/pump combo can typically be attached to the inside of the case with a mounting bracket. Because of the specifics of my design, I chose a dedicated stand with a rather nifty heatsink. It is a Swiftech MCP35X-HS DDC Heatsink, and it fits my case perfectly (Figure 6).
Figure 6. The XSPC acrylic reservoir, Laing DDC pump, mounted on top of the Swiftech MCP35X-HS DDC Heatsink
CPU water block
Most modern water block support both Intel and AMD CPUs. I chose the relatively new XSPC RayStorm water block for my AMD CPU. It is supposed to be very efficient and it looks great, having a nice brushed aluminium finish that matches the Lian Li case very nicely. It also as the inlet and outlet ports far enough way from each other to allow the mounting of 45-degree fittings. Additionally, it comes with a pair of LEDs that can be inserted into water block, making it glow very nicely inside the case (Figure 7).
Figure 7. XSPC CPU water block with a pair of blue LEDs
GPU water block
I am using an AMD Radeon HD 6970 SAPPHIRE 100311-2SR video card in this build. It is the second revision of the AMD reference design. While most CPU water blocks will work with just about any modern CPU, video card water blocks are specific almost exclusively to NVIDIA or AMD reference designs. A reference PCB is a design that the chipset manufacturers provide to the OEMs, such as EVGA, Sapphire, Asus, etc. However, quite frequently, manufactures modify the reference design to meet their specific needs. It is, therefore, rather difficult to find a video card that will fit the available water blocks. It can be extremely frustrating, and often costly, to try to find the right video card. Fortunately, some water block manufacturers, such as EK and Swiftech, provide a list of compatible video cards. Still, such lists are often incomplete and out of date, so you should probably refer to discussion forums and ask the manufacturers directly to be absolutely sure that the water block is going to fit the video card. I was originally going to buy an EK water block for my AMD video card, but they were out of stock everywhere, at the time.
Therefore, I decided to try the Swiftech Komodo HD-6900-2 water block. Having read very positive reviews of Swiftech water blocks, especially, the NVIDIA Hydro Copper series, I was fairly confident the water block was going to be good enough for my needs. I was not disappointed. It is a really nicely made, full-cover water block, and, most importantly, it fits my Sapphire Radeon HD 6970 video card perfectly (Figure 8).
Figure 8. The Swiftech Komodo water block mounted on the Radeon HD 6970 video card
Fitting a water block on the video card can be rather tedious, so you must follow the user's manual (alas, they're usually badly written and vague!), make sure you have the right tools and a lot of patience. First, we need to remove the plastic cover with the attached heatsink and fan. It is attached to the PCB with several screws. Once the screws have been removed, the cover needs to be separated from the video card. This may be a little tricky and might require a little bit of gentle force. Next, the surface area of the GPU, RAM blocks, and voltage regulators needs to be thoroughly cleaned, preferably with ArctiClean or an equivalent cleaning agent. Now, a small amount of non-conductive thermal compound needs to be gently applied to those surfaces.
Finally, the water block needs to be attached to the video card. Assuming we bought one that is designed the this particular PCB, we should have no trouble fitting it onto the video card. All that's left to do is fasten the water block with the provided screws. The screws are rather small so one needs to be careful not to accidentally strip the thread or damage the screw head with an incorrect-size screwdriver. Additionally, some types of water blocks might include brittle acrylic material, so they need to be handled with care.
All of the major water cooling components we have assembled so far come with standard 1/4-inch threaded openings for attaching fittings (so-called "G 1/4"). Fittings make it possible to connect all the pieces of a water cooling loop with tubing. The sheer multitude of different types of fittings can be a bit confusing. We should first decide on the diameter of tubing we are going to use throughout the loop. The two most common sizes are 1/2-inch and 3/8-inch in diameter. This is the diameter that determines the inner diameter (ID) of the tubing. Additionally, some types of fittings (e.g., compression fittings) have a specified outer diameter, which, in turn determines the outer diameter (OD) of the tubing. The most common OD sizes are 3/4-inch and 5/8-inch. The other important characteristic of a water cooling fitting involves the method by which tubing is attached to it.
The two most common types are barbs and compression fittings. Barbs are the simplest type of fittings. The tube simply slides onto them and needs to be secured with a clamp or zip tie. Compression fittings, on the other hand, offer an extra ring that seals the tubing and secures it in places. Some argue that compression fittings provide a more secure, leak-proof seal than barbs. However, they are slightly more bulky than barbs and may not fit water blocks with tight spacing between the inlet and outlet ports. Finally, water cooling fittings range in complexity, such as straight, 45-degree, 90-degree, rotary, etc. There are a great many types of adapters, extenders, splitters, etc., many which may be required in certain loops, especially space-saving or aesthetic reasons. These days, most fittings are beautifully made and come in a variety of colors and surface finish. Most water cooling enthusiasts agree that Bitspower and Koolance make the best fittings. It is probably not a good idea to try to save money on fittings. They are an important part of the loop and play a crucial role in preventing leaks and ensuring proper coolant flow.
Figure 9. Bitspower straight and 45-degree rotary barb fittings
For the purposes of this build, I chose barb fittings, both straight, as well as 45- and 90-degree rotary (Figure 9). I understand the limitations of barbs, but I appreciate their simplicity, small size, and overall looks. I decided not to use an claps for securing the tubing. Instead, I chose a slightly undersized diameter tubing: 7/16-inch, instead of the usual 1/2-inch (ID). The undersized tubing is more difficult to slide onto a barb, but once it is properly installed, it remains tight and leak-proof. I used a little bit of water-based lubricant to help slide the tubing on, which proved to be far easier than trying to force the tubing on or dip it in hot water in order to expand it.
The diameter of the fitting determines the diameter of the tubing. For barbs, only the inner diameter of the tubing matters, while for compression fittings, the tubing must match both the ID and OD of the fitting. There are many different types of tubing available, in different colors, with different stiffness and ability to bend without kinking. Tubing is not merely a conduit for the coolant, but it is also a highly visible part of the loop, so it should be chosen wisely in order for the loop to be both clean and functional. I chose the laboratory-grade Tygon 7/16-inch, clear tubing for this particular build.
My goal in designing the loop was to use as little tubing as possible by minimizing the distance between the contiguous components of the loop. Not only does this provide a cleaner-looking loop, but also ensures high-pressure, least obstructed coolant flow.
The simplest type of coolant is distilled water. Some people add dyes, anti-corrosive agents. I chose the PrimoChill ICE non-conductive water cooling fluid.
Putting it together.
The loop stars with the reservoir, which sits directly on top of the Laing DDC pump. The fluid moves to the CPU block, the GPU block, the radiator, and back to the reservoir. The arrows in Figure 10 indicate the direction of coolant flow. The total length of tubing is less than 35 centimeters. After the loop has been filled and the pump started (it's important never to run the pump dry), it is a good idea to keep a close eye on the system for a few hours, making sure there is no leak. Also, the loop will almost always require some bleeding, i.e., getting rid of air bubbles that will initially be trapped in it. This may simply require tilting the system a little bit to give the air bubbles an opportunity to escape. Afterwards, the fill port in the reservoir can be closed, and the system will be ready for installing the operating system.
Figure 10. Direction of coolant flow in my water cooling loop
Having connected all the cooling components, it is not important to fine-tune their performance. Some users may require the system to always operate at its top cooling capacity, while others would prefer to optimize the PC for quiet operation. I think it might be useful to add an easy way to control the rotational speed of the cooling fans and the pump. This can be accomplished by means of a fan controller that is typically installed in a 5.25 or 3.5-inch drive bay. I am using a Sunbeamtech PL-RS-3. It is a three-channel device that can work either in manual or automatic (PWM) mode. It's simple, but effective.
Finally, a lot of PC builders sleeve some of the ugly power supply cables. Here is a close-up of the PCI-E cables sleeved using the MDPC-X black and navy blue sleeving, in an effort to fit the overall color scheme of the build (Figure 11).
Figure 11. PCI-E cables sleeved using the MDPC-X black and navy blue sleeving
A water cooled PC has special appeal to computer builders. One of the measures of success is cooling performance, especially for overclocked systems. I am only a moderate overclocker, so my results should be treated accordingly. I overclocked the CPU to 3.8 GHz, and ran the usual stress tests that push the CPU and GPU performance to the maximum, for at approximately 30 minutes, with all cooling fans at a low setting (< 1,000 RPM). The results are summarized in the table below. The numbers speak for themselves; the system has a lot of thermal headroom, thanks to, in large part, to the superior cooling properties of water. The CPU block produced surprisingly good results. The GPU is a bit warmer than I'd expected, but it is placed right after the CPU in the loop, so perhaps a different placement would have resulted in lower temperatures.
|Test w/ ambient at 18C||CPU temperature (C)||GPU temperature(C)|
|Prime95 & FurMark||41||59|
While building a water cooling system requires considerably more effort and cost, it provides a challenging and enjoyable experience, far beyond that of a simple air-cooled PC. In addition, a well-designed water cooled system offers truly superior thermal performance and will benefit scientific applications, 3D media creation, and modern video games alike. I strongly encourage you to give water cooling a try.
Figure 12. The finished product