Watercooling requires a bit of knowledge and preparation. In this section I will cover what are needed, how it´s connected and I will give a few good advices I have learnt the hard way.
A decent watercooling system will bring temperatures measures on GPU and CPU down with typically 15-30C under load, when compared to decent aircoolers, and in the same time make the system less noisy. Choosing the right parts can bring temperature even closer to ambient temperature, but the biggest win is the design of the cooling setup.
Parts
Radiator ($35 - $200)
Fans ($20 - $300)
Tube ($15 - $60)
Fittings ($20 - $100)
Waterblocks ($45 - $250)
Pump ($50 - $120)
Reservoir ($30 - $70)
Fluids ($10 - $20)
Thermal Grease ($5 - $20)
Prices are not always a measurement of performance or quality. In watercooling many components are improved for show-off and by then pretty expensive, because of the look of it.
In general
There are two very important things in watercooling;
1) Flow
2) Heat dissipation.
Each of these parameters needs to be take into consideration for each component choosen for the system.
Flow
Flow is important, because you want water in the blocks to be as close to ambient temperature as possible. Leaving the water for more than a split second will heat it, and you want cold water all the time - the water needs to travel really fast through the system. A single restrictive component can break down a good watercooling system.
Heat dissipation
For Heat dissipation you need a radiator and some cold air traveling over that radiator. Depending on the amount of heat that needs to be dissipated, the size of the radiator is important. I dont think anybody have ever regrettet an investment in a radiator that was to big for the job. To help dissipation fans are equipped to force air through it.
The shopping list
The radiator
Find out what you can fit in your computer. The radiator needs a lot of air, so you have to put it somewhere, where you can be sure it gets fresh air directly. The air that cools the radiator will be the factor that give you the minimum water temps. Go for the biggest possible radiator you can fit in.
A radiator can fx be 3x120 which means that the cooling area can be covered by 3 pcs. of 120mm fans. My advice is to get a 3x120 or bigger. A 3x120 will be able to cool a CPU and GPU with no problems. If you want to go SLI/CX or cool other stuff like chipset and memory you might want something bigger. Better radiator can be a 4x120 or an 3x140, which will have more cooling area, but will be more expensive and might be difficult to fit into a normal computer case.
Different well known radiators can be seen here:
HWlabs (special in radiators)
Remember to pick something with highflow.
The waterblocks
Each component in the system that needs to be watercooled, needs to be cooled by a waterblock. Typical watercooling will go on CPU and Graphics card (GPU) which typically heat up a lot. Other stuff that can be watercooled is chipset and memory - but the benefit here is limited, and by adding these to a watercooling loop, will just decrease the flow.
CPU waterblock
CPU blocks are usually generics, and works on most sockets, you might however need to check that you get the parts that makes it fit your socket before ordering. Be sure to get something that are high-flow. CPU blocks can be really restrictive and its bad for performance.
Different well known waterblocks can be seen here:
GPU / Graphicscard waterblock
GPU blocks can be divided up in 2 different categories. There is the category for GPU blocks that will only cover the GPU, and then there is the category with blocks covering the whole card, which also includes memory and powerregulator chips (PWM /VRM). No matter which type of solution you pick, you can be pretty sure you ruin your warranty on you GFX when you equip it.
If you pick the GPU block, you need buy heatsinks for memory and PWM. Its a bit messy but can be done. The good thing about the GPU block is that it can usually be used again and again, and will fit all kinds of cards.
If you go with the fullcover, be sure you have a reference pcb graphics card, and that the fullcover block you choose, is mentioned in the compatability guide. A fullcover will only work on the PCB it was ment for.
GPU blocks, including fullcover arent usually very restrictive, but be sure its mentioned that they are high-flow before buying.
A word about waterblocks: Try to keep all blocks of the same materials. Using different materials can harm the system. Use copper on all blocks or use nickel on all blocks, dont mix it.
Pump
The pump in the system can be the most critical part. Its something you want to go, and go, and go. The day it die, your water will boil and hell will break loose, but it will happen. Because of that, you need something reliable. Second of that it can be a noisy part. What you want is a good, reliable, quiet pump that can provide a good high flow to your system. You want something that theoretically can move 800-1000 liter/hours. Pumps like that are typically from these providers, and some of them require a special pump head. You can do without and later on upgrade.
Often used pumps are also Laing DDC and D5. Laing pumps are reliable and close to unhearable.
Reservoir
The reservoir might not be a need-to-have, but it makes filling the watercooling system a lot easier. The main problem with reservoirs is that they decrease flow and in a high-flow system have difficulties to handle the flow, resulting in creating loads of bubbles which is really bad. I cant really say that I prefer any reservoirs, because every single reservoir have issues, so its to pick the best of something where nothing is close to perfect.
Beware that a bad reservoir that cause bubbles to the system can ruin the pump. The pump needs steady water coming.
Fittings
Reservoir, GPU block, CPU block, Radiator, Pump will all need a least 2 fittings each. The fitting is the part where the component are attached to the tube. The fitting needs to be sized to the component, and have the size of the inner diameter of the tube. The fitting is connected to the component with a typical size called "G1/4". From there its up to you how fat the tubes need to be. Lets say you go all in with 19/13mm tube, which is big, you need a "G1/4 -19/13" fitting. If you find 19mm thing tube a bit overkill you can go lower, but I recommend not to go beyond an inner diameter of 10mm. There are diffent kinds of fittings, normal and compression fittings. Compression fittings are really safe, when it comes to leakage, but pretty annoying when you want to connect / disconnect tube.
Bitspower (really good quality, and price is low)
Be sure to get highflow fittings.
Tube
Get 3-4 meters of tube, so you have a little if you cut something in wrong length, you will if you designed your system well, be using less than 1,5 meter of tube. Be sure that you buy tube that have the right inner diameter, compared to your choice of fittings. If you get the right size it will stick really well. Tube can be nice to look at, so you might want to get it in a color, or black. If your design require you to make some hard bends, you can get some kink coil, and when you do that, be sure the kink coil fits the outer diameter of your choice of tube.
Fans
Fans are needed for ensuring that air are traveling over the dissipation area of the radiator and for that mounted directly. You need to find fans that fits the radiator, which will be 120mm fans for a 120.3 radiator, or 140mm for 140.3 radiator.
Fans that runs fast with high static pressure performs better, but are typically noisy. I recommend to find fans that runs with a speed of 1000 - 1200 rpm., which can be done close to noiseless, and in the sametime give the radiator the air that are needed for a good overclocked system. Be sure to get at least 3, if your radiator support it. Best configuration on rads are to make them push air into the radiator. If you want more, you can get twice the amount and make push and pull, equipping fans on each site. Push/pull are overkill, but if you really want, its a little improvement.
Different good fans can be found here:
If the watercooling system will be visible from outside, you might want to choose some pre-modded fans, with light or so.
Fluids
You can get all kinds of fluid, and with colours and effects added to it. Normal water will be transfering the heat best, but you cant use that, because it has minerals in it, and it wont last long. You have to eigther buy premade water, or make you own by getting destilled/demineralized water and add some additives to take away bacterias. The more stuff you put in the water, the worse it gets on transfering heat, think about that.
Thermal grease
Finally, when you attach the waterblocks, you will need thermal grease. On GPU / Graphics card it might be needed with something that are non-conductive. Usually that kind of grease arent the best, but it can be close to and its wont shortcut anything. I recommend simple products like arctic cooling and arctic silver that can be bought everywhere. You will need something like 0,2g (a grain) for each waterblock so you can manage with a little tube.