Since watercooling is localized, that
means that each country has it’s own manufacturers and/or importers,
I can’t make complete reviews or comparisons between components since
they are too many and designed for different purposes, I will however
mention some companies or components as examples and comment on them,
the most widely available and known that I can think of at this time.
Of course you may easily find a product globally through resellers or
international shipping, as with most major companies and internet shops,
however it may be very hard as well at some places of the world. Also
such a comparison can’t be made, at least not while staying accurate,
since most products can’t be found anywhere but near their region of
origin and are designed with different concepts in mind. If anyone feels
that wants to ask my personal opinion about any given component, he/she
can send me a personal message.

picture1 Watercooling Guide

Water Blocks

Water blocks are the parts of a watercooling system that draw the heat
that components radiate. They draw the heat from the component and then
the water flowing through them absorbs it. They are pieces of metal,
mainly copper and in rare cases silver that through 2 or more holes
water circulates in them. Although there are blocks made from aluminum
as well, these are a waste of money and time. Aluminum cannot absorb
the heat as fast as copper from the component, neither releases the
heat fast to the liquid, so it can be very ineffective and worse than
an average air-cooling solution. Silver is one of the best metals for
heat transfer; however it’s very expensive, hard to be worked and is
damaged very easily. That leaves only copper, which is just a tiny bit
inferior to the silver, but it’s cheap, very sturdy and very effective.

Waterblocks that exist mainly are meant for cooling of CPUs, GPUs, motherboard
chipsets and HDDs. I’ve recently seen some ‘blocks’ for other components
as well, like PSUs, but they aren’t mainstream yet and still don’t help
much.

Example of waterblocks:

picture2 Watercooling Guide

Radiators

Radiators are the part of the system that water moves through them,
expelling the heat that it carries on the radiator which in turn releases
it on its surrounding enviroment. The surrounding enviroment is in most
situations air but not in all.

There are 2 types of radiators mainly. The first type are tube type
radiators, which are mainly a tube, usually copper, making many passes
through a ‘net’ of metal fins, usually aluminum. This way the heat from
the water passes through the tube to the fins and then released on the
enviroment. This design is very good performer when designed well and
an awful performer if the design is bad. The many curves and long pipe
length will hinder the flow badly when the design is bad, or its ability
to radiate the heat will be minimal.

Examples of a tube type radiators:

picture3 Watercooling Guide

The second type are fin type radiators. Those are often referred as
heatercores in most countries due to their use in cars. These basically
work by having a small tank in both sides and many tiny fins-tubes that
move the water from the one tank to the other. This way, water comes
in and gathers in the first tank, moves through the many little fins
to the other tank while releasing its heat on the enviroment, moves
from the other tank to the first and then goes back to the system. These
are rather efficient radiators, small in size but easy to be damaged.
The more dense the fin construction, the best performance you’ll get
usually.

Examples of a fin type radiators:

picture4 Watercooling Guide

Many may say that there is a third type, the stacked plate radiators.
However these are based on the same theory of the fin type radiators,
with merely the change of design. Instead of fins there are many metallic
plates stacked close together all across the radiator. These aren’t
widely used anymore, in my opinion because they aren’t so easy to use
and mount fans on them, plus their performance doesn’t really excel
anything else.

Alternatively, you can use a car/motorcycle radiator, given that it’s
good enough for the job, which are very cheap. However, it must be either
large enough to have no need of fans to expel the heat on the air, which
is not recommended unless you are after a quiet system and not lower
temperatures, or you must make yourself a mounting system for the fans.
Many people make shrouds out of plexiglass or aluminum; however that
will require proper equipment and skill. Also the proper tubing connectors
must be soldered on the radiator. If you have those requirements, you
can get a good radiator for even less than 1/5 the price you’d get a
commercial one sometimes. If you don’t, you better pay for one specifically
made for watercooling.

Commercial watercooling radiators usually have fan mountings, so that
you can use fans to pull or push air through them for it to expel the
heat on the air. For fans, slow-medium speed fans are more than enough.
Regarding 120mm fans, 1500-1800 RPM fans do the job just fine. Anything
stronger and the noise may increase dramatically from the airflow resistance
(backpressure) of the radiator.

Pumps

The pump, as its name suggests is what moves the water throughout the
system. The most widely used pumps plus harder to damage and somewhat
expensive are the magnetic drive pumps which use a magnetic field to
drive their vanes. There is also gear, piston and impeller type pumps,
but are not as widely used, because their performance degrades over
time and get damaged easily, or simply they aren’t powerful enough,
too large or very expensive. Performance of the pumps is measured by
their flow rate (L/H or GPH, which is liters or gallons per hour) and
their head delivery capability (meters/feet). Although most people only
look at the L/H numbers, I insist that the head delivery capability
is more important. It’s the height that the pump can send the liquid.
It also reflects the ability of the pump to overcome obstacles that
will find in any watercooled system, such as the waterblocks resistance.
Also, some people look at the amperage rating and power consumption
of a pump. In most cases, that will reflect how much the pump will heat
up, heating the water a little as well.

The only pumps I’ve seen that are perfect for watercooling systems are
the Eheim pumps line. They are the only that won’t degrade in less that
2 years of use, they won’t get damaged if there is anything that hinders
water flow in the system (like a radiator with a lot or small channels
or a block with bad flow) and they will hardly be damaged or hindered
by prolonged use, even working 24/7 for years. These are centrifugal
pumps, meaning that the spinning vanes will draw the liquid in the centre
of the pump and then eject it with a lot of strength due to centrifugal
force. Another good line of pumps and very much favored for their average
price are the Hydor pump line. They are quite strong and effective as
well as cheap, sometimes 50-60% cheaper than the Eheim pumps. However
I’ve noticed 2 flaws on them myself. First, they don’t like bad flow
setups or setups with many blocks and elbows since they degrade somewhat
easily if they find resistance. Second, unlike the Eheim pumps they
do heat up a little themselves, naturally like every pump, but heat
up the water slightly as well.

I don’t have opinion on every other brand (can anyone have?), but out
of the 5-6 I’ve seen, tested and used, the Eheim line are the only that
can do the job really done safely for an extended period of time. Of
course some other pumps do the job well enough, just not as good as
an Eheim would in my opinion but surely for less money or much stronger
performance for the same price. I do strongly recommend the use of a
reliable brand pump, because damage to the pump can cause disastrous
results. Also take note that any pump requires power of course and all
are made to take power from a power plug, so an extra wire has to get
out of your case most usually. Furthermore, check on the pump tube fittings
as well to make sure it matches your tubing. Not all use the same fittings,
although there are adapters for most cases.

Example of pumps:

picture5 Watercooling Guide