In the pantheon of nerd achievement, water cooling ranks near the top—somewhere between installing Linux and becoming fluent in Klingon. And there’s a reason the hardest of the hardcore prefer water cooling: It’s incredibly effective at lowering the temperatures of core system components. With higher thermal conductivity and specific heat capacity than air coolers, water cooling can mean double-digit drops in CPU and GPU temperatures.
However, water cooling isn’t exactly a walk in the park. You’ve got two challenges ahead of yourself: Designing the water-cooling system that’s right for your PC, and actually putting it together. Both tasks will take some time and effort, but neither has to be daunting. Every first-time water-cooling build is a learn-as-you go experience, but we’ll walk you through the details and help you avoid the mistakes that would take the biggest toll on your system and your wallet.
Pick Your Water-Cooling Components
The advantage of a custom water-cooling system is that it’s just that—custom. By picking out exactly which parts you want, you’re able to create a system that matches your cooling needs and your aesthetic sensibilities. To get you started building your system, we’ll go through every major component of a water-cooling system, describing what each one does, and what your options are.
Even though there’s no fluid touching your case, it’s one of the most important parts of a good water-cooling setup. For water cooling, you’ll need a case with plenty of room on the inside and a large fan grate, ideally on the top or bottom of the case. Although it can be a little hard on the wallet, getting a case that’s been designed with water cooling in mind will ensure that your install goes as smoothly as possible. In our build, we used the Corsair Obsidian 800D full-tower case.
A block is the piece of hardware responsible for drawing heat out of your computer hardware (your CPU and GPU, for instance) and into the liquid coolant in a water-cooling system. A block of heat-conducting metal makes contact with your CPU or GPU (aided by thermal paste) on one side, while water is forced across the other, literally flushing away excess heat.
You need a separate block for each component you want to cool. The obvious component to water cool is your CPU, which will see some of the greatest benefit in the form of increased overclocking potential. The GPU on your videocard is another good candidate for water cooling, as is your chipset. For this build we’ve chosen to focus on CPU and GPU cooling.
As for actually picking which water block to use, it’s generally a matter of brand and the right block for your part. For instance, if you’re using a socket 1156 CPU, a quick Internet search for “socket 1156 water block” will turn up a handful of compatible water blocks, as well as some performance comparisons. We’ve chosen CPU and GPU blocks made by DangerDen (www.dangerden.com).
In a water-cooling setup, the radiator is the water block’s complement, releasing heat absorbed from the block into the air. It accomplishes this by forcing the liquid coolant through an array of thin tubes attached to metal fins. Traditional case fans pull air through the capillary-like radiator, absorbing heat from the liquid and forcing it out of the case.
There are radiators big enough to support one, two, or three fans. Of course, bigger radiators and more fans amount to better cooling, so we generally recommend going with the biggest radiator that fits your case and your budget.
The fanciest water-cooling equipment in the world won’t do a thing unless the water’s moving through it, and that’s accomplished with a pump. There are quite a few pumps on the market, and although it’s on the pricier side, we recommend the Laing DDC 3.25 for its reliability and small formfactor. If you go with a different pump, make sure to read user reviews before you buy—a shoddy pump will wear out or break down over time.
In water cooling, a reservoir is a pretty simple thing—it’s a tank of water, with an inlet and an outlet. You might wonder why, exactly, you need a big tank of water in your system, since it doesn’t have an immediate function, like absorbing or dispelling heat. However, the reservoir performs a number of important duties:
A reservoir has a port on it, which allows you to actually fill your water-cooling system with liquid.
A reservoir generally isn’t filled all the way to the top with liquid. The extra air provides a buffer, which gives the liquid room to expand and contract as it changes temperature.
Because the reservoir is not entirely full, it also provides a place for air bubbles in the liquid to escape, which makes for greater cooling efficiency and quieter operation.
As for which reservoir to use—well, it’s really just a tank; pick one that fits in your case and looks nice. For this build, we used a double optical-drive bay acrylic reservoir from Danger Den, which comes with a pair of Molex-powered LEDs to light up the front of your case.
Tubing and Fittings
Finally, you need tubing to combine all the other parts. The most common sizes of tubing used are 1/2-inch and 3/8-inch diameter. The demonstrable performance difference between the two sizes of tubing is slim, and 3/8-inch tubing can bend more without kinking, so we used that for our system. Whichever you pick, just make sure that all the rest of your water-cooling hardware has fittings of the same size. Most all hardware is available with either 1/2-inch or 3/8-inch fittings; if you get a size that doesn’t match your tubing, you’re hosed.
Beyond the diameter of the tubing, you just need to pick a color. Most sites that deal in water cooling sell pretty much the same PVC-based tubing. It works well, it’s fairly cheap, and it’s available in a bunch of UV-reactive colors. Some sites offer slightly more expensive Tygon tubing, which is more flexible and durable. Fittings come in barbed or compression styles. Both will work just fine, though compression fittings look nicer and are a bit more expensive.
You’ll also need coolant to put into your system. Although it’s commonly referred to as “water cooling,” most modern cooling systems use some sort of coolant with anti-corrosive and anti-conductive properties. This fluid is available from any distributor of liquid-cooling products, and comes in various UV-reactive colors.
Once you’ve picked out the individual components, you’ll need to design the layout of your water-cooling system. For this, it helps to make a simple diagram, showing how you want everything to be hooked up. A simple system has the water passing from the radiator to the CPU, then to the GPU, the reservoir, pump, and finally, back to the radiator. This design works well because then the water passes over the CPU while it’s at its coolest, and also because the CPU and the GPU tend to be physically near each other.
Before we actually start installing anything, have a good long look at your case, and consider where each component will sit. Is there a clear pathway for the tubing to run from one component to the next? When the tubing is in place, will it be difficult to access other hardware, such as hard drives or optical drives? Will you be able to get the sides back on the case? By considering potential hazards like these now, you can save yourself a lot of headaches further down the road.
Finally, it’s time to discuss the actual installation of water-cooling hardware.
1. Mount the CPU Water Block
We recommend starting with the CPU water block, because it usually installs with a mounting backplate, so you’ll need to install it before you can screw the motherboard to the case, and you don’t want to install any other component until the motherboard is securely in place.
Your experience may vary, depending on what CPU block and motherboard you use, but for us the water block was a fairly standard backplate cooler installation. The opening in the motherboard tray on our Corsair 800D case made the process easy.
Connect the tubing to the CPU block before you install it, since it can take some pressure to get the tubing snugly into the fittings, and it’s always best to avoid putting extra pressure on the motherboard if possible. Now, attach the motherboard to the case.
2. Attach the Radiator
Now we can move onto the radiator, the largest component. The radiator can be installed over any fan grate that’s large enough, and most simple radiators are designed with screw holes that have the same dimensions as standard case fans. Thus, if your case has a grate big enough for two fans, you can mount a double fan–size radiator onto it. You can mount a radiator inside or outside of a case, but make sure that the fans blow hot air out of the case and away from your PC’s hardware. If you mount the fans outside the case, make sure you’ve got a plan for how you’re going to plug them into your power supply.
Once the radiator is in place, cut the tubing from the CPU to the right length and connect it to the radiator, making sure not to kink it in the process.
3. Affix the Reservoir
Continuing with the practice of installing largest parts first, it’s time to install the reservoir. There’s a wide variety of reservoirs available to suit your setup. They can be attached inside or outside of the case, to the radiator, or into a drive bay. No matter what style of reservoir you have, take note of the location of the fill port, and have a plan for how to access that port when it comes time to fill your cooling system with liquid.
4. Mount the GPU Block
Finally, we’ll close off the loop by installing the GPU block, assuming you want one. Some of the highest temperatures in your system can be found on your videocard, so there are definite advantages to water cooling it. At the same time, it’s also one of the riskier aspects of liquid cooling, since you have to remove your videocard’s existing cooler, directly exposing its processing cores.
Every GPU block install process is unique, so check the directions that came with the block you purchased. Generally speaking, it will go something like this:
1.Remove the videocard’s built-in cooler by unscrewing it from the board or boards.
2. Clean up leftover thermal paste and reapply paste or thermal material to contact spots, as illustrated on your instruction sheet.
3. Attach the board or boards to the water block, being careful not to apply uneven pressure to the processors.
Since GPU cooling blocks tend to be big, heavy hunks of metal, make sure to secure your videocard tightly to your case after plugging it into one of your PCI-E slots. If you don’t secure it, it can warp your motherboard, which will ruin it. Being careful not to put too much pressure on the card, connect the GPU water block to the CPU block and the reservoir.
5. Add the Pump
The pump should be really easy to install. Most pumps are fairly small and can be attached almost anywhere in your case, using screws or Velcro tape. Next, complete your loop by connecting the output barb of the pump (usually marked with an arrow pointing away from the pump) to the radiator, and the input barb to the reservoir. When you’re cutting tubing, don’t just go with the shortest amount possible—also consider how the tubing will affect how you access your PC hardware. You don’t want to have to dismantle half your water-cooling system just to swap out a hard drive.
6. Get Those Juices Flowing!
Now that your water-cooling loop is completed, it’s time to add the coolant. Give your system one last sanity check, making sure that each fitting is tightly connected, and that all components are hooked up in one continuous loop. Once you’re confident that your system won’t leak, and without plugging anything in, start filling up the reservoir to the manufacturer’s recommended level. Keep an eye on the rest of the water-cooling system, and be ready with a towel in case anything springs a leak.
With the reservoir filled with coolant, you can now fire up the pump. You don’t want to actually turn on your motherboard yet, so you’ll need to trick the power supply into powering the pump. Generally, this is done by shorting the green wire on the power supply’s ATX connector to one of the black wires, although it’s wise to consult the manual for your specific power supply.
As long as nothing is leaking, let the pump run for 10 minutes or so to let air bubbles escape. Slowly rock your case back and forth, to let any air that’s trapped in the water blocks or radiator escape. Once all the air bubbles are out of the liquid (you should be able to see them in the tubes if there are any left), you may need to add more liquid to the reservoir to reach the recommended level.
As you can see, although water cooling provides exceptional cooling power, it isn’t the easiest—or cheapest—way to cool your PC. If you just want to cool your CPU more effectively and quietly than a performance air cooler but without the hassle of building a custom water-cooling rig, there’s an alternative: a prebuilt, closed-loop system like the Corsair Cooling Hydro Series H50 or the CoolIT ECO.
These systems achieve cooling performance near that of a custom water-cooling rig, but save you the hassle of building one yourself, or ever having to replace the fluid. They cost more than an air cooler, but significantly less than building your own water-cooling system. And, unlike full-blown water coolers, they’re easy to install and don’t take up much room in your case.
Installation for this type of cooler is simple. It’s a backplate-mounted water block for the CPU, connected to a small, one-fan radiator. You just attach the radiator and fan to an exhaust grate on your case, and that’s it; the pump and reservoir are built into the radiator.
You won’t get quite the same CPU cooling as in an all-out water-cooling system—or the nerd cred that comes from a tower full of tubes—but closed-loop coolers are definitely an excellent alternative for enthusiasts who want some extra cooling performance without a lot of hassle.
How to Monitor Your PC's Temperature
Whether you overclock, or just want to make sure your processor lasts as long as possible, it’s important to keep an eye on your system’s temperatures. These two free programs help you do just that.
SpeedFan uses the built-in temperature-monitoring hardware in your chips to display temperatures for all of your individual components, and it allows you to control fan speeds in your case automatically, based on temperature readings. SpeedFan also monitors S.M.A.R.T. readings and analysis, so you can make sure your hard drives are healthy. (www.almico.com/speedfan.php)
From CPUID, the makers of CPUZ, HWMonitor keeps track of all the temperatures and voltages in your system. It doesn’t have the advanced S.M.A.R.T. features or fan-speed controls of SpeedFan, but its temperature-reporting functionality is top-notch. (www.cpuid.com/hwmonitor.php)