First Watercooling Loop

Radiators

I get asked a lot the question “what radiator should I buy”. There is no definite answer because the answer to that question is simply another question: “what fans are you running?”

The size of the fan determines the width and possible options for the radiator while the RPM of your fan determines the approximate FPI (fins per inch) of the radiator you desire. High speed fans (2000rpm+) work well with fin dense radiators (20fpi+), while low speed fans (1200rpm) work more optimally with low FPI rads (10 and lower). This is not to say that a low FPI rad will work better with a low speed fan than a high speed fan after all for radiators higher airflow through the radiator always results in better cooling.

The most important factor is really how much radiator surface area can you fit. The frontal surface area (i.e. the area which the fans will blow air over) is the single biggest factor in cooling performance. Therefore almost every other decision should be second to this. A thin triple radiator is a better choice than a thick double radiator.

The second factor is then how much space do you have for the radiator. I.E. radiator thickness. Typically 60mm thick radiators generally seem pretty optimal for most fan setups. Going thicker tends to require higher speed/pressure fans, while going thinner generally loses some small amount of performance. Bear in mind that space may determine whether you run fans on both sides of the radiator or only one. Choosing a thinner radiator with fans on both sides will again usually perform better but will typically cost more because of the extra fans.

There are also quality issues to consider as well as case compatibility issues to consider. Not all radiators have quite the same fan spacing, nor do all the endtanks overshoot the standard radiator mounts by the same amount. Most radiators are cheaply made in China by a different supplier to the guy putting their logo on them which is why they all look so similar. You can easily tell the ones that aren’t made in China mainly because the cost is so much higher but also because the designs look very different.

Martin did an excellent roundup on radiators recently where the Alphacool UT60 range performed excellently across many fan configurations. The only issue with these radiators are a slight conflict with some cases where the extra G 1/4 ports can clash with the case mount (though this depends on your configuration and can be solved with some rubber gaskets to space them.