I tested EK Nucleus AIO CR360 Lux D-RGB earlier and so far this cooler has been a top performer in our graphs. This time around I am looking at the 240mm version of Nucleus AIO from EK Water Blocks. This is EK-Nucleus AIO CR240 Dark. Dark here refers to the all-black color scheme of the unit without any RGB lighting effects. This cooler is compatible with Intel LGA1700 and AMD AM5 sockets in addition to support for other sockets. This cooler has the same EL-Omnilink technology that makes the cable handling convenient, new positioning of tubes for better clearance, a new pump design, and a dense micro fin copper cold plate. The pump top is still rotatable though there is no A-RGB lighting over it in the Dark variant.

Product:               EK Nucleus AIO CR240 Dark

Price:                     USD $91.19 [At the time of this writing]

EK-Nucleus AIO CR240 Specifications

EK Nucleus AIO CR240 Dark Specifications

Packaging and Unboxing

The EK-Nucleus AIO CR240 is shipped inside a white-themed packaging box made of cardboard material.

EK Nucleus AIO CR240 Dark Packing Box 1

There is a picture of a unit over front view of the packing box. This unit is compatible with:

Intel Sockets LGA: 1150, 1151, 1155, 1156, 1200, 2011, 2011-3, 2066 + Next-gen Intel Socket, 1700

AMD Socket: AM4, AM5

EK Nucleus AIO CR240 Dark Packing Box 2

Salient features of the unit are printed over here including:

  • 5-Year Warranty
  • Easy Installation
  • Socket Compatibility
  • Circular Design
  • Easy Cable Management

EK Nucleus AIO CR240 Dark Packing Box 3

There is a thick black Styrofoam pad into which the cooler and fans are tucked. There is another orange color container placed on the side with the caution text on this side up. It has accessories.

EK-Nucleus AIO CR240 Accessories

Let’s see what is provided in the accessories department.

EK Nucleus AIO CR240 Dark Accessories 1

EK Water Blocks has provided:

  • 1x Intel Mounting bracket
  • 1x AMD Mounting bracket
  • 1x Intel LGA1700 backplate
  • 1x Intel other sockets backplate

Besides, a comprehensive user guide with pictures provides installation guidelines on supported sockets.

EK Nucleus AIO CR240 Dark Accessories 2 1

There are:

  • 4x Thumb Nuts with Springs
  • 4x Intel LGA20xx thumb screws
  • 4x Intel/AMD thumb screws
  • 8x Philips UNC 6-32x30mm Fan Screws
  • 8x Philips UNC 6-32x34mm Fan Screws
  • 8x Philips UNC 6-32x6mm Radiator Screws
  • 4x Philips Head M3x4mm Mounting Bracket Screws
  • 1x ECO-TIM Thermal Paste Tube
  • Micro-Fit 8-Pin Connector Cable
  • Tool for easy installation/Removal

EK Nucleus AIO CR360 Lux D RGB Tool 1

EK Water Blocks has provided a tool. This is to install the thumb screws on the backplate through the mounting holes near the socket area. While you may not pay attention to this at first, this is a blessing when working with a space-constrained area near socket area particularly the top leftmost mounting hole that sits close to the capacitors of the VRM area. I appreciate EK Water Blocks for thinking this deeply and providing a simple solution.

EK Nucleus AIO CR360 Lux D RGB Tool 3

There are two holes on the body of this tool on the opposite side. EKWB was thinking ahead. These would come in handy when removing the thumb screws from the motherboard. But one thing they missed in my opinion is the provision of a cross-bar or cross-beam that can be attached to this tool and provides a convenient way to remove or install the thumb screws.

Closer Look

Let’s dive into some details on the EK-Nucleus AIO CR240.

EK Nucleus AIO CR240 Dark Radiator 1

EK Water Blocks uses an aluminum-made radiator which is a universal design perspective unless otherwise stated. The radiator has a dimension of 281x124x27mm (LxWxH). This unit has a thickness of 27mm and it would come to 56mm approximately after installing fans (27mm thickness of EK Loop FPT fans). This radiator has a FPI count of 20 and it has a total of 12 channels for coolant flow. The mounting holes on opposite ends have a standard gap of 105mm. EK Water Blocks has done a nice job in fin stacking on this unit. We did not observe any bend or broken fin.

EK Nucleus AIO CR240 Dark Radiator 2

The far end has a rectangular layout without any branding over it.

EK Nucleus AIO CR240 Dark Radiator 3

Looking at the near block or the tube connection side, we notice that this design differs from the design of the EK-Nucleus AIO CR360 Lux A-RGB cooler. The connection of tubes with the fittings is not hidden on the CR240 Dark. Clamps are concealing this connection and there is possibly a third port that could very well be to refill the unit. There is a large size cap over this port and it has a warranty void sticker that implies that this port is reserved for factory use only.

EK Nucleus AIO CR240 Dark Radiator 4

This unit does not have a diamond-cut brushed aluminum plating on the side frame of the radiator. The side frames have a simple layout without any branding. The gap between the actual fin stack and the side frame is reduced providing more surface area. There is no protective plating under mounting holes. This unit uses Ultra-Low evaporation rubber tubes with fine threading. There is a fine nylon braided mesh sleeve on the tubes which is aesthetic purpose. This tube runs to approximately 370mm excluding the connections.

EK Nucleus AIO CR240 Dark Block 1

The block design on this unit is a different design. The pump housing has a dimension of 82.3×69.2×61.6mm and it is made of ABS material. The pump top is made of ABS material as well. This design is almost a circular one. The block seems to be a large size. The sides of the pump housing have a simple black finish without any branding.

EK Nucleus AIO CR240 Dark Block 2

The pump top on the EK-Nucleus AIO CR240 is removable and rotatable. There is an EK logo that can be used to grab the top and lift it off. There is no digital RGB LEDs in the Dark edition hence you would not get to see the funnel-looking digital RGB lighting effect.

EK Nucleus AIO CR240 Dark Block 3

The above picture shows the inside of the pump housing after removing top cover. There is no 3-pin pad on any corner. This is because there are no RGB LEDs housed inside hence no active connection is needed.

EK Nucleus AIO CR240 Dark Block 4

The above picture shows the inside of the pump top. Seems like EK Water Blocks uses a standard top on all versions with or without a 3-pin connection since we can spot the funnel design carved inside.

EK Nucleus AIO CR240 Dark Block 5

Looking at the backside, we can see two tube connections at a 90° angle. These are using rotary fittings and this time around, EK has narrowed the gap between the connections. According to EK, this would help install this unit in space-constrained areas.  There is a single flat cable coming out under the tube connection.

EK Nucleus AIO CR240 Dark Block 6 1

The cable has a 4-pin PWM connector to power the pump.

EK Nucleus AIO CR240 Dark Block 6

This unit comes with pre-applied thermal paste and EK Water Blocks has also provided a tube of thermal paste in addition. The copper base measures roughly 38x38mm. The copper cold plate of this unit has dense microfins for efficient heat transfer. There are 4x golden color holes on the ABS housing above the copper base. The mounting bracket is installed on these holes. The PWM range of the pump is 20~100% and has a speed range of 3100 RPM ±10%.

EK Nucleus AIO CR240 Dark Fan 1

EKWB has provided EK-Loop FPT fans. FPT stands for Full Pressure Technology. These fans feature a full frame design that does not allow air to escape and helps in maintaining the pressure. There are 7 blades per fan with a large diameter center with EKWB branding. The holes between the corners and the inner ring are covered from the rear side. The backside of the fan has an X-shaped arms design. EK-FPT FAN – 120ER is the model of the fan. We can see the power rating of this fan as well. Each mounting corner has a black color anti-vibration pad.

EK Nucleus AIO CR240 Dark Fan 2

Each fan has a small size cable tucked to one side of the frame. These fans feature the EK-Omnilink concept where EKWB uses an 8-pin microfit connector to daisy-chain the fans. This reduces the cable clutter and only one cable comes out to be handled by the user. There is a single cable that comes out from the daisy-chained fans. This cable has a 4-pin PWM connector on the other end that is to be connected to the motherboard.

EK Nucleus AIO CR240 Dark Fan 3

The above picture shows both fans inter-connected using 8-pin microfit connectors. Each fan has a male and female connector on a single cable to allow daisy-chaining. Salient specifications of these fans include:

Dimension 120x120x27mm
Speed Range 550 – 2300 RPM ±10%
Noise Level 36 dB(A)
Air Flow 72 CFM
Static Pressure 2.7mmH₂O
Bearing Fluid Dynamic Bearings


We are not covering the details of installation for the EK-Nucleus AIO CR240. Installation is a breeze and we did not observe any peculiar issue to report. The tool makes life easier and we can install this cooler even with more confidence than before. Please refer to the user guide for more details.


We have used the following configurations for testing:

  • Intel core i7 12700k
  • Sabrent Rocket 32GB DDR5 Kit @ 4800MHz CAS 40
  • Sabrent Rocket Q 500GB NVMe SSD [For OS]
  • Be quiet! Straight Power 11 850W Platinum PSU
  • Thermaltake Core P6 TG Snow Edition in an open frame layout

Test table for Intel core i7 12700k is:

Clocks P-Cores 4.8GHz

E-Core 3.8GHz

Voltage 1.20V
C-States Disabled
Speed Step Disabled
Rest of settings Stock, Auto
XMP XMP Loaded where available
Thermal Paste Noctua NT-H1
Thermal Paste Application X lines method
Headers CPU_FAN, CPU_OPT, and PUMP Headers
Stress Software CINEBENCH R23.2
Stress Run Time 30 minutes
PC Idle Time 5 minutes
Monitoring Software HWInfo64
OC Tool Intel XTU

EK Nucleus AIO CR240 Dark Test Build

A bit of note about the new platforms. We have seen AMD AM5 and Intel Alder Lake S CPUs taking more power and this time both sides have aimed at reaching the maximum clocks regardless of thermal limit. In fact, the AM5 SKUs will run into thermal limits right away depending on the cooling solution and the clocks being used. This has made testing of CPU coolers challenging because viewers/readers are not used to a new nomenclature which is what clocks are sustained under a given load using a particular cooler. That is if the cooler is capable of providing enough cooling head to sustain the high frequencies. Traditionally we are used to going the other way around that is which cooler is better in terms of thermal capacity. Despite this, we are using temperatures as a base for measuring this unit. Among other reasons is the high thermal density of these new CPUs.

The ambient temperature was in the range of 25°C to 25.5°C. Since the variation in the ambient temperature is within 1°C, we are reporting absolute temperatures in the graph. The testing is done on an open-air bench system. Once inside the chassis, the temperatures are expected to rise and would largely depend upon the optimal airflow inside the chassis.

Disclaimer: Every silicon is different hence no two same SKUs are likely to take same voltage to yield same performance at same thermals per se but margin would be close. Not every stress test run may yield the same result which could be due to various reasons like thermal paste application, ambient temperature variation, mounting pressure of the cooler etc. This is why we have listed our variables and their settings. Let’s take a look at the results.


EK Nucleus AIO CR240 Dark Thermal Performance

This is a solid performance of the EK-Nucleus AIO CR240. It is challenging the big guns in 360mm size easily. EK Water Blocks means business and their coolers deliver a solid punch.


Our sound meter shows this unit making a sound output of 50 dB(A) at an ambient of 32 dB(A). This is a good all-around performance from EK Nucleus AIO CR240 Dark.


Nucleus is a new generation of AIO coolers from EK Water Blocks. EKWB has released two broader categories in this new generation. They are named LUX and DARK. As the name indicates, the LUX series of coolers pack digital RGB lighting effects whereas the DARK series of coolers have a black color theme. LUX series also has white edition coolers. So far, 240mm and 360mm size coolers have been made available. We have tested EK Nucleus AIO CR360 Lux D-RGB earlier. This time we have tested the little brethren namely EK-Nucleus AIO CR240 Dark.

The EK-Nucleus AIO CR240 Dark is compatible with Intel LGA115x, 1200, 1700, 2011, 2011-3, and 2066 + Next-Gen Intel socket. On the red camp, this unit is compatible with AMD AM4 and AM5 sockets. The DARK version of the Nucleus series of coolers has no D-RGB lighting effects. This is one of the prime differences. The rest of the differences come from the brushed aluminum plating on LUX series of the coolers and the full block coverage on the radiator that sits flushed with the 120x27mm EK-Loop FPT fans. The DARK series of coolers don’t have these features. Other than that, both series have the same fans and the same pump so expect some good performance anyway.

This cooler has an aluminum-made radiator having a dimension of 281x124x27mm (LxWxH). 27mm is height of this radiator. Since this cooler comes with 27mm thick fans, the overall height of this unit would be 56mm approximately including the heads of the Philips screws. FPI count is 20 and there are 12 coolant flow channels.

EKWB uses ultra-low evaporation rubber tubes with nylon braided mesh sleeves. These tubes have a length of 370mm including the fittings. Speaking of fittings, this generation is still using rotary fittings but this time EKWAB has reduced the gap between the tube ends to make this even more compatible in tight spaces.

The pump housing has an unconventional design though it is still somewhat circular. It is made of ABS material. The pump top is rotatable so that the EKWB logo remains upright. There are no D-RGB LEDs inside the main housing hence you are only losing the funnel-style RGB lighting effect without losing the performance. This unit has a copper base having dense microfins making up the copper cold plate for efficient heat transfer.

EKWB has employed a PWM-controlled pump having a PWM duty cycle of 20% ~ 100% rotating at 3100 RPM ±10%. EKWB has provided their EK-Loop FPT fans with this cooler. These fans feature a closed frame design that prevents air from escaping and it would help in maintaining the pressure. EK has also introduced an EK-Omnilink concept with this generation. Each fan has a tied-up cable of short length. One end of this cable has a female micro-fit 8-pin connector and the other end has a male 8-pin micro-fit connector. These connectors are daisy-chained to each other and then there is a single extension cable providing a 4-pin PWM connector and digital RGB connectors. Kudos to EKWB for making cable management an easier job! These fans are using fluid dynamic bearings and are rated for 550 ~ 2300 RPM ±10% speed generating a maximum of 72 CFM airflow at a static pressure of 2.7mmH₂O (figure taken from fan’s webpage). These fans are rated at 36 dB(A). I have seen a similar cabling design on the Enermax Liamaxpro 360 liquid cooler. Seems like others have started to follow this trend!

I have always found it difficult to install a thumb screw or bolt on the top left side of the near socket area for the installation of the cooler particularly on the Intel 12th generation and onward. Finally, someone has paid attention to this and has provided a simple yet effective solution. There is a tool included in the accessories exactly for this problem. With the new tool, it is easy to install or remove these thumb screws without risking the capacitors sitting closer to the mounting holes. One thing that is missing is the cross-bar that could be passed through this tool and acts like a handle using which screws can be removed with relative ease. Hands down to EKWB for this simple solution and I hope others will follow it or come up with their solution.

I have tested this cooler on an Intel LGA1700 socket. Installation is easy and involves 10 items for block installation on this socket. I did not observe any issues during installation. There is no D-RGB lighting on this unit and it is better suited for black/neutral theme builds at its best.

The EK-Nucleus AIO CR240 Dark is listed at USD 91.19 at the time of this writing. This is a competitive pricing and EKWB has made it a more appealing proposal with 5+1 years of warranty. But wait, what about the performance? Well, in my testing, this 240mm liquid cooler actually was giving a few 360mm liquid coolers a run for their money. Much like the CR360 Lux which is still out number 1 contender in the graph, this little master is now sitting comfortably among the performance level of 360mm size coolers.


  • Excellent Thermal Performance
  • Rotatable Pump Top
  • All Black Theme
  • EK-FPT 120mm Fans
  • Easy Cable Management using EK-OmniLink
  • Intel Next-gen Socket support
  • Easy Installation
  • 6-year Warranty
  • Price


  • None

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