MaximumPC 2006 09

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The diameter of the inlet and outlet ports on the water

blocks, pump, and reservoir will determine the size of

the tubing you use. The most common way to identify

tubing size is by its internal diameter, also known as

ID. As a rule of thumb, wider-ID tubing delivers a high-

er fl ow rate. The higher the fl ow rate, the more cooling

power a kit can bring to bear. The industry has settled

on fat, 1/2-inch tubing for high performance water-

cooling. Most other kits use 3/8-inch tubing, and some

lesser kits even use 1/4-inch tubing. We recommend

1/2-inch tubing for maximum fl ow.

The type of tubing varies as well, but not radically.

Most tubes are made from either Tygon, silicone, or just

generic vinyl. Tygon is very expensive but bends well

and doesn’t crimp easily. Silicone is very fl exible, but not

widely available. And thus, we come to the most com-

mon type of tubing:

vinyl. It’s cheap,

works well, and is

readily available.

TUBING

The Black Ice Xtreme is the

de facto radiator used in

almost every kit available.

WATER BLOCKS

A water block is a copper heatsink

that’s mounted to your CPU or GPU to

absorb the heat generated by that com-

ponent. There are a zillion water-block

designs on the market, and each manu-

facturer claims that its design is the

best, based on its own internal testing.

We’ve tested almost every big-name

water block on the market, and though

we’ve defi nitely seen differences among

them, the performance delta is usually

slight. Even the worst blocks provide

decent performance, but some are bet-

ter than others.

The differentiation point in water

blocks is the path that water takes

through the block. Some water blocks

use simple channels carved in an “S”

pattern, which is a rather rudimentary—

yet effective—design that’s cheap to

manufacture. Other water-block manu-

facturers are now advocating a more

sophisticated design known as the “pin

matrix.” Once water enters one of these

blocks, it’s forced through a grid of ver-

tical pins. This design offers more sur-

face area than “S” pattern designs, and

more surface area means better cooling

performance.

Aside from the radiator and tubing

size, the type of water block you use

has the biggest impact on a water-

cooling kit’s performance. The most

important trait to look for when pur-

chasing a block is that its inlet/outlet

barbs match the tubing diameter

of your other hardware. Aside from

that, you’ll want a water block with

a low pressure drop, which ensures

the water keeps moving through the

block quickly. The best blocks we’ve

tested are the Danger Den TDX and

Swiftech’s Apogee, which both use a

pin matrix design.

The Swiftech block keeps the

water moving at a high rate of speed by

squirting it down onto the middle of the

block (right above where the CPU core

is located) through a process called

jet impingement. The water jet creates

major turbulence where the water con-

tacts the block, which helps transfer

heat away from the block.

The radiator transfers heat from your water-cooling circuit to

the environment outside your case. It’s where the heat from

your water-cooled components radiates out of the system.

Aluminum is the most popular material for radiators because

it’s light, inexpensive, and can be crafted into very complex

shapes—much more easily than copper. Most radiators

are designed to work with a single 12cm fan, for maximum

cooling with minimum noise. The more surface area on your

radiator, the more heat it will be able to pull from your cool-

ant, so some extremely high-end kits employ larger radia-

tors, or even multiple radiators. In our tests, we’ve found

that a single 12cm radiator is suffi cient to cool a high-end

CPU and GPU.

Which radiator is best? Every high-end kit we’ve tested

has included the exact same radiator: the Black Ice Xtreme. It

features fl at aluminum water

channels among a dense

array of louvered fi ns. It

doesn’t require a lot of air-

fl ow to keep it cool, which

makes for quiet computing.

Water blocks come in a wide assort-

ment of shapes, sizes, and designs.

No, it’s not trans-

parent pasta. Tygon

tubing is very thick,

yet easy to bend.

RADIATOR