What size radiator do I need for my system?

A very hot airflow from radiator fans is a sign of a system running at - or over - it's maximum cooling capacity.

Water needs to be adequately cooled with the coldest ambient air temperatures. Therefore, the radiator should be getting as much "fresh air" as possible. Hot air from the radiator should also be driven out of the computer chassis by auxiliary chassis fans. Poor design and construction choice may result in insufficient radiator cooling, which may lead to overheating of the components. In the case of cooling capacity issues, the symptoms are usually a slow but steady increase in temperatures until the system reaches equilibrium or encounters stability issues.

The benefit of a custom water cooling loop is that the system can be expanded, and the cooling capacity extended almost without limitations.

The rule of thumb is to use at least one 120mm radiator (section) per each water cooled component plus one additional section.

For example, if you're liquid-cooling a CPU and a single high-performance graphics card, it is recommended you use at least one 240mm (2x 120mm) radiator for good performance. Ideally, you would get a 360mm (3x 120mm) radiator for the best results. Motherboard and memory water blocks usually have lower power output, and therefore they are not included in this equation.

Radiators also come in different sizes, but the 120mm type is the most common. For example, a 280mm radiator (2x 140mm), built for 140mm cooling fans, has a 33% larger cooling surface than the 240mm variant (2x 120mm), meaning it can dissipate substantially more heat given the same conditions. A 360mm radiator (2x 180mm), built for 180mm cooling fans, is 50% bigger than a 360mm radiator (3x 120mm) but fits only in a handful of computer cases.

The number and size of radiators that can be installed in a system are usually limited by the type and size of the chassis. That is why EK recommends the use of larger, water-cooling friendly computer chassis.

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  • 0
    Joseph Armeni

    Do you guys think a predator 280 with 2x 140mm Noctua NF-A14 + 2x 140mm EK vardar fans it comes with in push/pull can sufficiently cool a delidded kaby lake (91 watt tdp) running @ 5.0ghz at 60C + CPU motherboard VRM + Full water block Coverage GTX 1070 (150 watt TDP) with all the extra tubing bought ofc? In a basement that is always a bit cooler than room temp around 20C for room temp. The CPU VRMS also receive passive air cooling from the 2x 140mm intake fans on the front of the case as well as the 140mm exhaust fan on rear of case. The CPU VRM Heat sink block is a combo water/air block built by EK for ASUS so the VRMS would not solely depend on the water. The GPU will be full coverage as in gpu chip gpu vrms and gpu memory receiving nothing but water cooling no air at all.

    The PSU's heat will be isolated drawing cool air from the bottom vent of the case and  venting it right out the back plus it will be an 80+ titanium 12 year warranty seasonic prime unit with as little waste heat as possible to begin with.


    And would it be possible to get the PWM pump and fans to ramp up not only from cpu usage but also from GPU usage as in either/or will cause it to ramp up regardless of the state of the other? If the CPU starts getting used it ramps up if the gpu starts getting used it ramps up even if just the gpu is really working hard but the CPU isn't will the fan and pumps still go fast to keep the gpu cool?

    Edited by Joseph Armeni
  • 2
    Ivan Filatov

    Radiators tdp watts only in configurator, why not to put them on product page?

    Edited by Ivan Filatov
  • 0
    EKWB Support (Peter)

    Dear Joseph & Ivan,
    Thank you for your comments.

    @Joseph: Your questions has already been answered by my colleague Grega in March 2017.
    If you would have any other technical questions, please do not hesitate in contacting our Technical Support Team at support@ekwb.com

    @Ivan: Thank you for your feedback - we have already notified our IT Department to put the TDP in the radiators product descriptions. The feature should be implemented soon.

    Edited by EKWB Support (Peter)
  • 0
    Nathan Villani

    Hi Guys, any update on getting the Watts on the Page for Rads, still only showing in the Configurator. 

  • 0
    EKWB Support (Peter)

    Dear Nathan,

    Your question has already been answered today by my colleague Grega in your ticket #159324.

    Thank you for your patience and understanding.

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