Seidon 240M

Disclaimer: Displayed parts and accessories may not be included in the actual product package.

The Seidon 240M is Cooler Master’s latest addition to its incredibly compact watercooling kit line that aims to bring watercooling to the masses. It fits in many cases that support 2 x 120mm fan radiators, is compatible with every available Intel and AMD platform, and is as easy to install as traditional heatsink. It comes factory filled, sealed and tested with a two year zero maintenance guarantee. Thanks to two 120mm PWM fans with a wide RPM range, Seidon can operate silently or unleash a powerful cooling storm at your command.

  • Factory filled with coolant, then sealed and pressure tested - requires zero maintenance for years.
  • Waterblock made with UltraFine Micro Channel enlarge the contact surface between cold plate and coolant.
  • Durable and powerful water pump – dissipates heat effectively and maintains temperatures through stable water circulation.
  • Performance 240mm radiator is designed for handling high wattage overclocked CPU.
  • Double 120mm PWM fan with a wide RPM range to fine tune and balance fan noise and performance.


Model RL-S24M-24PK-R1
CPU Socket Intel LGA 2011 / 1366 / 1156 / 1155 / 1150 / 775

AMD Socket FM2 / FM1 / AM3+ / AM3 / AM2+ / AM2
Pump Dimensions ø 70 x 27mm (ø 2.75 x 1.1 inch)
Radiator Dimensions 273 x 120 x 27 mm (10.7 x 4.7 x 1.1 inch)
Radiator Material Aluminum
Fan Dimension 120 x 120 x 25 mm (4.7 x 4.7 x 1 in)
Fan Speed 600~2400 RPM (PWM) ± 10%
Fan Airflow 19.17 ~ 86.15 CFM ± 10%
Fan Air Pressure 0.31 ~ 4.16 mm H2O ± 10%
Fan Life Expectancy 40,000 hours
Fan Noise Level (dB-A) 19 ~ 40 dBA
Fan Bearing Type Rifle bearing
Fan Connector 4-Pin
Fan Rated Voltage 12 VDC
Fan Rated Current 0.2 A
Fan Power Consumption 3.6 W
Pump Life Expectancy 70,000 hrs
Pump Noise Level <25 dBA
Pump Rated Voltage 12 VDC
Pump Load Current 0.15 A
Pump Power Consumption 1.8W
Warranty 2 years
UPC Code 884102020049
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    • Click logo to read full review:  Silver : June 2013

      "The Cooler Master Seidon 240M can be called a top shelf liquid cooling system.  It performed almost as well as the best watercoolers we have tested to date.  It is also easy to install and relatively affordable."

      » Details  Great Hardware : June 2013

      "Overall the Seidon is a great unit. It’s built well and it shows. The sleeving is a good quality and every single cable is sleeved, including the “Y” splitter. The cooler performed flawlessly and was easily able to handle the heat of a good overclock."

      » Details Diamond Award : June 2013

      "The Cooler Master Seidon 240M is an all around great choice if you are looking to keep your CPU running cooler especially under overclocked conditions. Temperatures were by far the lowest we've seen therefore we highly recommend this cooler to the PC enthusiast crowd. Installing the Seidon 240M was simple and straightforward though a little time consuming."

      » Details : May 2013

      "Cooler Master's Seidon liquid coolers are one of the only pre-filled CPU water cooling units that are NOT based on Asetek or CoolIT designs. Cooler Master built their own like a boss."



      » Details  9/10 : April 2013

      "the Cooler Master Seidon 240M does not let down as a AIO liquid cooling product. Playing games such as Dota 2 or Bioshock Infinite found temperatures less than 60 degrees Celsius in at least two consecutive matches in Dota 2 and playtime of 2 hours in Bioshock."




      » Details 9/10 : March 2013

      "With CM’s quality components and affordable pricing, the Seidon 240M can be a perfect fit for many users."

      » Details  Editors Choice : March 2013

      "Cooler Master’s Seidon 240M is an excellent no-compromise all-in-one quiet cooler for a reasonable price considering its build, ease of installation, and all-inclusive package. It is well-deserving of our “Editor’s Choice” award and it cools our own overclocked hot-running Ivy Bridge i7-3770K. Highly recommended!"

      » Details
      Hardwarecanucks - Dam Good Value : February 2013

      "Cooler Master’s Seidon 240M may not be without a few minor limitations, but overall it is still one of the best closed loop water cooling solutions currently available. If budget constraints place a Corsair H100i – let alone NZXT’s X60 - outside of your grasp, then the Seidon 240M would make an excellent price-conscious alternative."

      » Details Editors Choice : February 2013

      "The Cooler Master Seidon 240M Liquid CPU Cooler delivered excellent cooling performance under all conditions, the best I have seen from an AIO 240mm solution to date. I also like the fact that cooler master manufactured it themselves and didn’t use the same OEM pieces that we have seen before. In Cooler Master fashion, they took their own route and came out with something decidedly different.

      The assembly of the hardware was pretty straight forward and simple. There is one thing that was quite obviously wrong in my mind with it, though. The risers always seemed to back out with the hardware and not stay in place well at all when tightened as good as I could get them. I think a rubber washer instead of plastic would quickly solve this issue. The Cooler Master Seidon 240M Liquid CPU Cooler is priced at $104.95 and can also be found cheaper at some retailers and is worth every penny."

      » Details  Must Have Editors Choice : February 2013

      "It tops all the AIOs I have tested, and it beats the best air cooler!  The Seidon 240M is quite possibly gods send in AIO cooling, brought to you by Cooler Master."

      » Details Recommended : January 2013

      "The Seidon 240M can be found for $99.99, considerably less than the competition. This actually puts it in the same price range as a few of the 120mm coolers, especially kits that come with a push/pull fan setup. The extra surface area that the 240mm radiator affords you is a much better pick and can also be run in a push pull configuration if you would like......The next time you are in the market for a cooling solution the Seidon 240M is going to make your choice much easier. Why go with a 120mm cooler when you could get twice the radiator (unless it won’t fit in your case of course). "

      » Details  Editors Choice : January 2013

      "The real kicker on the Cooler Master Seidon 240M is the price point; $99.95 MSRP. So, you get better cooling performance, less noise, easy installation and setup, and top notch build quality for less than what we have been seeing. There has to be a downside, right? Well, if there is, I can’t find it. Cooler Master may have been late to releasing their AIO, but they are still the old pros in cooling and the Seidon 240M showcases their experience and innovation. With all of this going for it, can we possibly give the Cooler Master Seidon 240M anything but our highest award?"

      » Details Crowned Product Award : January 2013

      "At an MSRP of $99.99, Cooler Master also comes in $10-20 cheaper than the Corsair H100 series.  Cooler Master probably is afforded a bit more pricing flexibility since they manufacture the coolers and don't re-brand them from Asetek or CoolIT like most of the other all-in-one water cooling systems on the market.  For great acoustic and thermal performance, simple setup, and a competitive price, the Seidon 240M looks to be a winner for beginners to liquid cooling and enthusiasts alike."




      » Details  Highly Recommended : January 2013

      "The cooler performance of the Seidon 240M is right up there with the better of the 240mm all-in-one units, this includes the Thermaltake Water 2.0 Extreme and the Corsair H100i. We love of Cooler Master stepped outside the box with their version of the AIO cooler. No never do we have to look at the same two typical style head units we are accommodate to.

      We farther like the fact that Cooler Master did not complicate things with a lot of wiring coming out of the head unit or needing to be connected to it. This makes for a better looking install. And with eliminating the cables needed to go to a USB header, you miss out on have a dedicate AIO software suite like the Corsair and Thermaltake higher end models. We don’t see this as a big problem as many motherboard manufacturers make an application to allow you to adjust your fans or you can simply download a third party application like SpeedFan.

      Even with the Seidon 240M performing well, you still have the option of adding two more 120mm fans to the unit to configure a push/pull setup. This should be good for another couple of degree lower. "

      » Details
      PCWizKid: Recommended : January 2013  Seidon 240M water cooler review and installation on CM Storm Trooper enclosure.




      » Details Approved : January 2013

      "you have a cooler here that performs on par with other AIO units in its class and is actually $5 to $10 less than the Corsair H100i (depending on where you look). So, in the end, we have good performance at a great price, which makes it worthy of consideration if you are in the market for an all-in-one water cooling solution."

      » Details

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