Custom Water Cooling Hardware Guide

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If you have been looking to do water cooling for your rig, but weren’t sure where or how to start, this is the definite water cooling hardware guide to get you going. Learn what parts you need, and how to choose the best parts for your budget. Then once you get all your hardware in order, learn how to install them.

The Essentials

To get started with water cooling your PC, you need to grab these essentials. For beginners, there are kits to get you started that include everything, but you will quickly find out, that you will end up changing parts out to fit your specific needs or wants.

Some water cooling terminology:
Loop – A loop is a point where your water cooling system starts from and then cycles through the end returning to the starting point. A simple example of a loop would be from your reservoir to the pump, then the radiator and back to the pump.

rad – Radiator

Here is the checklist and what each component for water cooling does.

  • Pump – What the pump does is take water and push it through the system. There are a variety of pumps to choose from, and can range in price from about $30 – $300. When choosing a pump, you should take into consideration the size of your loop. The larger the loop, the more water flow you would want. To view how to spec out water pumps check the specs for the Swiftech MCP655 below:
    • Nominal voltage: 12 V DC Operating voltage range: 6 to 24 VDC Nominal power (@ 12 V): 24 W Nominal current (@ 12 V): 2 amps Motor type: Brushless, microprocessor controlled Maximum head: 13 ft (4 m)Maximum discharge: ~ 317 GPH (1200 LPH) Connection size: 1/2″ barbs (3/8″ w/ conversion kit) Maximum pressure: 50 PSI (3.5 BAR) Temperature range: 32 °F to 140°F (0 °C to 60 °C) Electrical connector: 4-pin Power Supply Connector Weight: 1.4 LB (650 gr.) Impeller Housing material: Noryl®
    • I have marked some of the more important specs in yellow. Lets go over those now.
      • Maximum Head – How high the water will lift. In this case, 13ft. The higher you go, the less water flow you will get. This rate here is pretty good, and chances are you dont have a case more than 4ft. tall.
      • Maximum Discharge – How much water the pump will push. The higher the water flow = faster water flow through your loop. For larger loops this is important. For smaller loops, this would be too much and in turn may not allow sufficient time for the water to circulate in the radiator to cool.
      • Connection Size – How big of fittings in which your tubing will connect. Think about the sizes like a straw. The smaller the size, the harder it is to push fluid through. The size is measured in outer diameter of the actual fitting where the size on the tube will be inner diameter.
      • Maximum Pressure – This says how much length that the rig will keep its strongest flow.
      •  To figure out the length of your most effective loop, work out this ratio with a positive flow remaining in the end.
        MH = 13
        Max PSI = 50
        LPH = 1200
        This means this pump will push 1200 LPH to a vertical distance of 10 ft. Ideally, you would want a pump that would push 500LPH to 2 water blocks a radiator and reservoir. So for this pump theoretically you could run 2 radiators, a cpu water block, and triple video card water blocks without much of a loss.Swiftech MCP655

        Pump flow rate vs pump head

        Pump flow rate vs pump head

  • Reservoir – The reservoir is basically a water storage and exchange unit. This is water ends up before it is recycled into the loop. Generally, the bigger the reservoir, the greater chance your loop has at maintaining a steady temperature. There are benefits of using smaller reservoirs though. One benefit is faster water transfer between your loop which in turn could allow for faster cooling. Again, this all depends on the size of your loop as well.If you have a larger loop, you would want to go for a larger size reservoir. This would be to ensure you have sufficient amount of water vs heat transfer in your loop. If you have a small res that is returning water too fast, temps would not have a chance to cool down while passing through the loop.Here are some examples of res vs water flow:
    • 250 ml (Flow rate ~ 50 GPH)
    • 500 ml (Flow rate ~ 100 GPH)
    • 1,000 ml (Flow rate ~ 150 GPH

Frozen Q Reservior

  • Water block – There are nickel based water blocks, and copper based. The copper based allows for a better heat dissipation, but it is very minimal. What is most important when choosing a water block is construction of the block including heat dissipating columns. Truthfully, most blocks these days are good, but some are better than others.Example of columns. This danger den shows off its heat dissipating columns
    water block
  • Tubing – Tubing is pretty simple to explain. You want a flexible and highly durable tube to allow your water to pass through. Choosing color is probably the hardest part here. The best choice is food grade tubing known as Tygon. This has natural defense against algae and other junk that can build up in your loop. It is also more expensive. As long as you’re using a silver kill coil, you can just use Primochill’s tubing.

    Silver Kill Coil

    Primochill Tubing
    Primochill Tubing

  • Fittings – For a fittings, they are pretty straight forward. You have 2 primary types.
    • Compression – Compression fittings allow you to securely fasten your tubing to your fitting without using zip-ties, clamps, or any other type of fastners.  They are essentially a 2 piece unit that screws into a water cooled component, and then allows the tubing to attach. Then the second piece fits over the tube and connector making a tightly sealed connection. Compression fittings are slightly more expensive, but make for more eye candy and security.
    • Barb – A standard connection that goes into the water cooled component and allows the tube to be fitted over. These generally need some sort of clamp or zip tie to keep tight onto the connection. Cheaper, and most common.
    • Angled fittings – Sometimes you may find the need to use angles to get your tubing right. For this there are angled fittings that can allow you to go 90+ degrees to get that right fit that would prevent kinking in your tubing.EK Compression Fittings
      EK Compression Fittings
  • Radiator – Found this article @

What radiator to use with x components is probably the most common question seen when getting into water cooling. It seems to be a very mystifying process that many people just can’t get a grasp around. Choosing the right parts the first time means less headache, and much less money spent.

Comments on message boards such as read the stickies, and go to this or that website, while good advice, can be very over whelming, and still not make the answer perfectly clear. I will be the first to admit that going to watercooling websites blind is one of the most overwhelming experiences in all of learning the art of water cooling.

There are numbers, and graphs, and phrases that make absolutely no sense and very little is done to prepare the new person for this amount of information overflow.

Understanding your wants. The first step in the process involves deciding what you want out of your cooling system.

Do you want a pure performance oriented loop that gives you the lowest possible temps, or perhaps you want a quiet set up that still maintains decent temps? Perhaps you would like a balance of the two?

This is a very relevent question. By answering this question first, it allows you to narrow down the amount of radiators in the market place.

Where will you mount your radiator? If you want to mount this radiator inside your case, will it fit? Will you need to mod your case? This is very important to keep in mind when choosing your components.

Maybe you can only fit a 120.2 radiator up top and you have decided you need a 120.3. You can always use a 120.2 and 120.1 to make up the full radiator.

Keep this in mind when you start looking for parts.

*NOTE* If you choose to break up your radiators, you will have to pay attention to pump selections. I will go over this in another hub. 120.1, 120.2, and 120.3 are descriptions of the radiator sizes. 120 stands for the size of the fan that will be mounted, and the second number is how many fans on that rad. So a 120.3 uses 3 120mm fans.

Understanding your heatload. Your heatload is the next step in choosing the proper radiator, but what is this and how do you find this out?
Heatload is the amount of thermal energy you need to dissipate from your loop. Too little rad and you have a hot cpu or very high speed fans; too much and you wasted money.
The answer to finding your heatload depends on one simple question. Is your cpu overclocked?

If the answer is no, simply search cpu name + tdp in google. I.E. If you have an I7 920 you would search for “I7 920 tdp.” The Intel site will be the first link and will tell you max tdp for that chip. In this chip’s case it’s 130 watts.

If the answer is yes it gets a little more complicated. By using the following formula, you can find the heatload of your overclocked chip.

((TDP*OCF)/SF)*(VC^2/VID^2) = Overclocked Heatload

TDP = Thermal Design Power (Point). Get this with google by using “<chip name> tdp.”
OCF = Overclocked Frequency in MHZ. This is how far you have overclocked to. If you have a 4ghz overclock, this entry will be 4000
SF = Stock Frequency in MHZ. This is pretty self explanatory. 2.66GHZ will be represented as 2660.
VC^2 = V Core squared. This is the V Core you have set for your overclock.
VID^2 = The stock V core setting. You can find this with google by using “<chip name> stock vcore.”

How to work this out.

Using an I7 920 overclocked to 4GHZ with a V Core setting of 1.23v we figure it as follows.


Start with the parenthesis of tdp*ocf.

130*4000 = 520,000

Then divide that by the sf

520,000/2660 = 195.4887218

Next square your vc/vid.

1.23*1.23 = 1.5129
1.27*1.27 = 1.6129

Then divide vc/vid

1.5129/1.6129 = 0.937999876

Now multiply the answer to the first parenthesis with the answer to the second parenthesis.

195.4887218*0.93799876 = 183.3683968 watts. This your heat load.

*NOTE* Since not all of the energy contained within a chip has to be removed you can multiply either of these with .8 to get a more realistic idea of your actual heatload. For the stock tdp it would equal 106 watts and the overclocked would be 147 watts.

Understanding Delta T Delta T is a fairly simple concept. Delta simply means a change, and T stands for Temperature.
In water cooling, Delta T (Known as DT) is the difference in the temperature of a stabilized water loop, and the ambient air temperature.
For instance, if you have an ambient temperature of 23 degrees Celsius and a water loop temperature of 29 degrees Celsius, then you have a DT of 6 degrees.
When water cooling a CPU, you want to shoot for a DT of 5 – 10 degrees Celsius.
*NOTE* I will cover how to find a theoretical DT later in the article. This is extremely important when you start selecting parts.

Understanding FPI For our purposes here we will say that you are looking for a quiet loop with good performance. You are cooling your overclocked i7 920 with 147 watts of power.

You look for your radiator, but with all the choices how do you choose one from another? Here we go over Fins Per Inch (FPI)

This is exactly what it sounds like. How many fins are in each inch of radiator.

Measuring Fins Per Inch

Using the above image you count each fin both up and down.This particular radiator has 8 fins per inch. 8 fpi.

But what does that mean? Well the lower the fin count, the lower the fan speeds you need, but also lower total performance. The higher the fpi, the higher the fan speed needs to be, and subsequently better total performance. It should be noted that lower performance is not a bad thing here. It is simply lower than the top performers, but gives quieter fan speeds.

So for our above requirements for a quiet system, we know we can look for lower fpi radiators.

For this article we will call low noise fan speeds 600-1200 rpm (8-12 fpi). Medium noise speed 1300-1800 (12-17 fpi). High noise speed 1900+ (18+fpi).

Going to We now have a better idea of the radiator we want to chose for our loop. We decided on a quiet set up that can remove 147 watts of cpu heat load. Time for our first trip to skinneelabs! is the premier website for obtaining non biased, real world results on the most popular water cooling products. Using this website you can pick the best products for your loop, and have full confidence that they will perform the way you need them to.
Going to Skinnees the first time can be very intimidating. There is a lot of information being presented, and very little explanation on how to use it. The great news? You, as a first timer looking, can throw most of the information away. Skinnee posts quite a bit of information to show how he came up with his analysis of a radiator.

There are several radiator reviews here, and the best thing I can tell you is to read the articles for the specs of the radiators looking for ones that fall in the fpi range we are looking for (8-12 FPI).

For the sake of simplicity I will use the classic Thermochill PA120.3. It has an FPI of 10 so it falls right in where we are wanting.

The first page is a general overview of the radiator in question. It tells us the fpi, the materials it’s made from, etc.

*NOTE* Always make sure your radiator uses brass and/or copper in its water tubes. The fins can be aluminium, but the tubes need to be the copper/brass. The reason for this is that mixing the copper in your water block with tubes made of aluminium will result in galvanic corrosion of your water block. That’s bad.

The second page is flow rate and pressure drop. The first table, you can mostly ignore it as you have no frame of reference for the numbers, however the wording of the article is very important. Using the graphs at the bottom of this page we see that the radiator in question has very low restriction, and that is a good thing.

The third page is about how he tests and what equipment he uses. You can skip most of this as it’s useless to us. There is one thing on this page, though, that you need to know about.

C/W. How skinnee gets his c/w is, in all honesty, irrelevent to us. However what you can use C/W for is very relevent to us. It will let us know what kind of Delta T,(You read that article above, right?), you can expect with what speed fans.

How you use C/W is you take C/W and multiply it by your heat load, and this tells you how much hotter your water loop will be over ambient air, i.e. your DT!

The fourth page has loads of information on it, and it’s this page that we can find out if our rad of choice will be able to handle our heatload (147 watts) with low speed fans (600-1200 rpm).

Thermochill Graph

You only need two pieces of info from this graph.

1. The fan speed on the far left.
2. The c/w that is outlined in yellow on the far right.

For the 600 rpm fan speed, we see it has an average C/W of 0.04180077. Now we multiply that by our heatload.

147*0.04180077 = 6.14471319 DT.

THIS IS GREAT! We know we are shooting for a DT between 5 and 10 degress Celsius. Looks like this is our rad.

If you continue down to the graph, you see that each of the lines represents a fan speed identified by the key at the top of the graph.


The purple line is the 600 rpm fan choice.

The numbers going up the left side represent your target DT.

The numbers going along the bottom are your heatload in 25 watt increments.

Following the heat load number over to 150 and heading up you will see where each fan speed crosses that line. The 600 fan speed is crossing right after the 6 degree Delta T mark. Perfect.

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