Water cooling a PC, in theory, isn’t difficult. There are only 5 or so parts to a water cooling system:
- A pump to move the water / coolant through the system.
- One or more radiators to transfer the heat out of the system.
- One or more fans to force air through the radiator(s).
- One or more water blocks attached to the parts to be cooled (CPU, Graphics Card, etc.)
- A reservoir used to hold the water (and provide for expansion and air trapping).
- And maybe not a component per se but still important: the tubing and fittings.
Of course in practice it gets a lot more complicated. A closed-loop water cooling system might sound simple but there are numerous factors that can affect how well the system performs, things such as how much heat is generated (which is determined by the CPU / graphics card(s) / etc. and the load that is placed on them), the flow rate of the water (which is determined by the pump size, tubing size and length, number and type of water blocks, number and type of radiators, number and type of fittings, and so on), the radiators and their efficiency at removing heat, the amount of air flow through the radiators, the ambient temperature, and probably several other factors I’ve forgotten.
Add to this the fact that every water cooling system is different and it can be seen that planning a water cooling system can be quite complex. And even reading forums and blogs written by other people (myself included) can add to the confusion because you’ll generally find contradictory information and recommendations (due in large part to the many different goals and type of systems people build). The only tried and true rule seems to be to trust your experience, of which I of course have none. So what to do?
Goals for my System
The first thing I did (after doing a lot of research – reading forums, blogs, etc.) was to decide on some goals for my system, the first being what to cool with the water system. You can actually get water blocks for the CPU, the graphics cards, components on the motherboard (such as the chipset and components used in the voltage regulators), and even the memory modules (RAM). The problem with trying to cool everything with water is that more water blocks require more pump power (since there’s more restriction on the system), more fittings, and most importantly you get more heat into the system and so need to get that heat out (i.e., bigger and/or more radiators and fans).
Since I plan on using a new motherboard the decision to water cool the motherboard doesn’t apply, at least for now (since there will be no water blocks available for my motherboard for awhile, if ever). Additionally, research I have done indicates that any benefit of water cooling RAM modules is usually not worth the added restriction and heat in the system. This leaves the CPU and the graphics card, which is what I have decided to put “under water”. These two parts generate the most heat, and I will gain the most benefit from water cooling these parts in terms of performance gain from overclocking.
A second goal for my system is for it to be quiet, at least no louder than any system I currently have and possibly even quieter. Noise in a PC primarily comes from the fans that move the air through the case, so this will be the main way I can combat noise. Additional noise comes from the power supply’s cooling fan (which is another benefit of choosing a larger power supply, by running it well below it’s maximum rating I can probably get it to be a little quieter than a fully loaded supply might be) and from the water pump.
A final goal which I have mentioned before is for the system to be as self-contained as possible, I don’t want tubing and cables running outside the case if at all possible. There’s nothing wrong with that, to be honest, it’s just that I own a cat who makes it his mission to investigate and “stress test” everything he possibly can. I just know that water tubes sticking out the back would call to him, begging him to play with them.
Selecting the Radiators
The first thing I chose was the radiators I wanted to use. Since I sort of know how much heat I will be adding to the system under full load (though the CPU is just a best estimate right now) I needed to make sure the radiators I chose were able to remove most of that heat (otherwise it wouldn’t really be cooling system).
And of course there are many, many models and types of radiators to choose. The first thing I did was to get as much surface area as I could fit in the top of my case. The way I figure it, the more radiator surface area I have the less air I will need to force through the radiators with fans, thus resulting in a quieter system. The second criteria in my radiator selection was to get radiators designed for low air flow as opposed to high air flow. Again, this should allow me to run quieter (slower) fans thus resulting in less overall system noise.
The radiators I chose were a Phobya Xtreme 200 radiator (200mm x 200mm) and an EK Coolstream RAD XTC 140 radiator (140mm x 140mm). This gives me a surface area of 59,600 mm2 which is a little over the surface area of a 480mm x 120mm radiator (the “standard” in water cooling radiators, at least in forums and such, seems to be 120mm wide radiators with the most common size used being a 360mm x 120mm radiator, also known as a 360 or 120.3). Based on the research I have done this would appear to be enough to be somewhere in the area of “more than enough” to “just enough” for the CPU and graphics card in my system.
For now I have chosen a single fan for each radiator, I am hoping that single fan per radiator will be enough (since these radiators are low airflow design). If necessary my mounting configuration allows me to add a second fan to each radiator to increase airflow if I find it is needed (in what is known as a "push/pull" configuration). I chose fans with high static pressure (which is key for forcing air through a radiator), a Noctua NF-P14 FLX for the EK radiator and a SilverStone AP181 for the Phobya radiator. The SilverStone appears to have excellent static pressure but is also a little louder at full RPM so I am hoping that I am able to run it at slower speeds and still get decent airflow, that fan might get changed out at some point.
The Water Pump
I chose a Laing DDC 3.25 pump. These pumps are one of the “standards” when it comes to PC water cooling and combine excellent flow and quiet running. I am replacing the standard pump “top” with an XSPC acrylic top which tests have shown increases the head pressure and flow rates the pump is able to put out (plus, it just looks cooler than the standard black top as pictured on the Laing page). I will also be mounting it using vibration-reducing bushings to further reduce the noise of the pump.
This is probably one of the biggest uncertainties I have right now with the system, is this a powerful enough pump? I have attempted to find flow rates for the various components I am using and compare them to published results for this pump, and from what I can tell I should be able to achieve at least 1.5 gpm (which is my target). My research has shown that at least 1.0 gpm is desirable (to prevent the water flow from becoming laminar in the radiator which reduces its ability to transfer heat) so I should be okay, but I have not been able to find definitive flow numbers on the radiator I have chosen so I have made some best-guess calculations here.
Reservoir
A reservoir does just what it sounds like it does: it holds water. Using a reservoir also provides a place for any air bubbles in the system to escape from the water / coolant as well as provide for any expansion and contraction of the coolant (though in a well-designed system there shouldn’t be much expansion going on). I chose a Koolance TNK-501 5 1/4” drive bay reservoir. It just has what I think is a clean look and doesn’t take up too much space.
Water Blocks
I have decided on EK water blocks for both the CPU (Supreme HF) and the graphics card (FC570 GTX SE), EK blocks get good reviews for both low restriction and good performance. Another plus is that EK has already announced support for the LGA 2011 CPUs. As is probably obvious the CPU block covers the CPU and is responsible for cooling the chip. The graphics block is a “full cover” block and cools not only the GPU on the graphics card but the graphics card’s RAM chips and voltage regulator chips and as such will replace the entire heatsink and fan assembly on the graphics card.
That’s about it for the main components of the cooling system. There is of course the tubing (I’ve selected PrimoFlex blue tubing, 3/8” ID x 5/8” OD) and fittings (I will be using matte black compression fittings from Bitspower), but those aren’t that exciting really. I will have 3 case fans to promote air circulation in the case and bring cool air into the case, one in front, one on the side panel (both 200mm CoolerMaster fans) and a smaller 120mm or 140mm fan in the back acting as an exhaust. I will also be using an Aquaero 5 fan / pump controller from Aquacomputer . I will detail my plans for that and reasoning behind using it in my next post...