We all know that many electronic components (particularly CPUs/GPUs) produce a lot of thermal energy (heat); this must in some way be dissipated to the ambient air; this is traditionally achieved through a combination of fans/heatsinks, the heatsinks serving to provide a larger contact area with the air to increase the amount of heat that can be transferred while the fans create air movement to result in a more efficient heat transfer process.
In more recent years (relatively speaking) we've seen the advent of chips with higher thermal loads, requiring larger heatsinks and more airflow. For this reason we've seen a lot more (and larger) heatpipe coolers on the market as they have significantly more surface area than the stock coolers; these coolers are often very heavy/bulky and can get in the way in the case and in some cases stress the motherboard in such a way that it could cause damage to the motherboard.
Watercooling then becomes a very viable option since water is very good at absorbing heat and can do so with a very low temperature change for a given amount of heat. The fact that water is a fluid makes it possible to physically move the heat away from the source and transfer the water to a more convenient location for dissipating the heat, namely the radiator. Since the radiator does not have to be physically attached to the heat source (only by means of tubing for the water to flow through), the surface area for heat transfer can be significantly larger than what could be achieved with a sink mounted on top of the CPU. This allows a lot more heat to be more effectively transferred from the CPU to the ambient air and thus also allow for lower idle and (more importantly) load temps than what can be obtained by means of air cooling.
What brands to consider/avoid
One word of warning for newbs is to avoid cheap kits from companies such as Koolance, Zalman and Thermaltake; they are crap and at best offer the same performance of a good heatpipe cooler. This can be attributed to poor block/radiator design making them less effective at transferring the heat to/from the water. Another reason to avoid these companies is that they generally use aluminum in their block tops and/or radiators, which can lead to galvanic corrosion between the copper in the bases of the blocks and the aluminum.
The companies I consider to produce the best watercooling components are DangerDen, EK-Waterblocks, D-Tek, Swiftech, Thermochill, Hardware Labs, and LIANG. Only current exception is the Swiftech Apogee GTX CPU waterblock and the Swiftech Stealth VGA waterblock as they have aluminum tops; however, for the Apogee GTX a replacement copper top is available.
Generally watercooling the chipset doesn't really provide much of a gain. The only situation where watercooling really becomes a valid option is when doing extreme overclocking.
Radiator selection is based on what you're planning on cooling, I generally recommend at least a 240mm rad (120mm are more for CPU only, 360mm+ for CPU and SLIed/X-fired GPUs); you can easily hang it from the rear of the case with a Swiftech RADbox or gutted 120mm fan. For low speed fans the Swiftech radiators perform a bit better than the HW labs GTS series; but if you can afford it, the Thermochill PA series are supposed to be the best available.
Currently the D-Tek Fuzion is considered to be the best CPU waterblock on the market, other good choices are the Swiftech Apogee GT and the DD TDX.
For GPU cooling you can either mount a core only waterblock and use heatsinks on the RAM/Vregs or use a full-cover waterblock that actively cools the core, RAM, and Vregs. Using a full-cover block is usually a bit more expensive than a block + sinks; however, with many newer graphics cards the price difference isn't as much since the cards require a lot more sinks than previous cards. If you plan on going the full-cover route, I'd probably recommend going with EK-waterblocks as they're a bit less expensive than the DangerDen blocks (and from what I hear also perform better). For core only blocks I'd recommend the Swiftech MCW-60, DangerDen Maze4 or DangerDen Maze5.
The two pumps I'd recommend are the LIANG D5 (aka Swiftech MCP655) or the LIANG DDC with Petra's Tech top (available from www.petrastechshop.com )
For tubing I generally use 1/2" ID, but if you need to make tighter bends, the best is to use 7/16" ID tubing on 1/2" barbs. I personally just use zip-ties rather than hose clamps on the fittings.
To fill the system there are two options; either to use a reservoir or a T-Line. Whichever you use it should be right before the pump in the loop order; this is to keep the pump flooded during the filling process (can be damaged if run dry). In some cases the reservoir is easier for filling the loop while the T-Line requires significantly less less space; but when it comes down to it it's just a matter of preference.
For cooling fluids I just use Distilled water + Biocide (algaecide), but the Pentosin would also be a viable choice; IMHO the pre-mixed coolants are a waste of money
Places to shop
Petra's Tech Shop - has very competitive prices and ships worldwide (orders outside the US are completed via email), also offers preconfigured "kits" consisting of quality components; the two owners are very knowledgeable and also very much interested in customer satisfaction
DangerDen - Web store for the waterblock manufacturer, also offers "kits" comprised of their products
Jab-Tech - Also offers competitive pricing and a broad selection of components
Swiftech - Wed store for Swiftech, also offers pre-made kits
Performance PCs - Good selection and decent pricing
Xoxide - decent selection but somewhat more expensive
FrozenCPU - good selection but somewhat more expensive
Sidewinder Computers - good selection and prices, ships worldwide
SVC - prices are comparable to Jab-Tech and Petra's Tech Shop
For those of you familiar with other resellers worth mentioning, pleas let me know and I'll gladly add them to the list.
Edited by radodrill, 24 May 2008 - 10:01 AM.