Have you ever wanted to spend the cost of a graphics card on your AIO cooler? Well look no further, the ROG Ryujin II 240mm from Asus is by far the most expensive cooler in this range we've held in our hands. What do you get for that cost? All of the features in a 240mm you could possible want? Perhaps. Asus has collaborated with Noctua with the Ryujin II, the AIO comes with two 120mm Noctua Chromax NF-F12 fans which are some of the best money can buy. It should be said this is only the case for the regular Ryujin II 240 we have here, the ARGB model comes with Asus' own fan. The features and benefits don't stop there though, you'll get a 3.5" customisable screen on your CPU block, an integrated VRM fan to help shift any warm, pooling air, and one of the nicest ARGB/fan controllers we've seen. Does it all justify the £239.99 price tag? That's up to you. What I can say is if you're a ROG fanatic this will be the best fit for your build. Whilst we are testing the 240mm variant, the Ryujin II comes in 360mm and ARGB flavours as well.

TL:DR - Pros and Cons

  • Noctua NF-F12 Fans as standard
  • Beautifully designed
  • 3.5" Directional screen
  • Rotatable mounting
  • Included ARGB & Fan Controller
  • Very expensive
  • Poor customisation options (Armory Crate)
  • External controller required

Initial Reactions

The unboxing experience for this cooler is traditional for a ROG product, with a booklet style box that unfolds to expose the cooler and all the other goodies. The stand out part on this cooler other than the beautifully crafted Noctua fans, is the absolute unit of a CPU block. It does house a screen and a VRM fan so the size isn't just wasted space, you're unlikely to run into any vertical limitations. In the majority of builds this block will look great and we feel the main bulk of it doesn't "stand out" as much anymore with many AIO coolers going down this trend of utilising more vertical space.
Depending on your preference, the Noctua fans will either look amazing, or very dull. At the end of the day these are just black fans with no lighting whatsoever. This doesn't take away from the fact it's all very aesthetically pleasing, this cooler would work quite well in a blackout build with just the CPU temperature or time displayed on the screen.
Apart from primary aesthetic, the tubing is nicely braided and very manoeuvrable with 90° fittings to the CPU block and with a fairly thin, flexible design, you get good movement. The core AIO itself including the pump design is from Asetek, we've reviewed Asetek hardware before, it's utilised by many different brands and can certainly hold its own.

Asus ROG Ryujin II 240 Technical Details

You can find the technical details and what you receive in the box below. It's interesting to note this cooler comes with a lovely controller for splitting ARGB, but doesn't actually have any ARGB elements on this model specifically. This controller comes with all coolers in the Ryujin II line-up.
  • Radiator Size - 240mm
  • Radiator Dimensions (WxDxH) - 121 x 27 x 272 mm
  • Radiator Material - Aluminium
  • Cold Plate Material - Copper
  • TDP - Not Listed
  • Radiator Fans Speed - 450-2000RPM +/- 10%
  • VRM Fan Speed - 4800RPM +/- 10%
  • Socket Compatibility Intel - 1700, 1200, 115x, 2011, 2011-3, 2066
  • Socket Compatibility AMD - AM5, AM4
  • Asus ROG Ryujin II 240 (Pre-applied thermal paste)
  • x2 Noctua NF-F12 120mm black fans
  • Asus mounting for supported sockets listed
  • Fan and ARGB controller
  • Manual and support documentation
  • Adhesive Tape and ROG sticker set
  • 1-to-2 Fan splitter cable
All included material with the Asus ROG Ryujin II 240 cooler

Testing Specification

For thermal testing we use a range of different software to stress the CPU including, Cinebench R23, Prime 95 Blend and Aida64 utilising AVX based tests. Temperature's are recorded using Aida64's temperature logging. Fan or pump speed (RPM) is not manually set or throttled for sound testing, including the VRM fan found in the ROG Ryujin II 240. The noise testing should represent your experience and what can be expected under general use. This isn't a scientific test per se, but is made to showcase the coolers capabilities with regular user conditions. Room ambient temperature is monitored and recorded before, during and after our testing and a Delta is calculated for the temperature over the recorded ambient room temperature which is used in all of our temperature charts. The CPU performance-core clock is locked 4.0 GHz and CPU core voltage is locked to 1.33v
  • CPU - AMD Ryzen 7 5700X
  • Motherboard - ROG STRIX X570-F
  • RAM - 16GB Corsair Vengeance LPX 3000 MHz (2 x 8GB)
  • SSD - Samsung 1TB 980 Pro
  • PSU - Corsair RM850x 850W
  • GPU - Nvidia RTX 3060 Ti
  • Case - Corsair 4000D Airflow

Performance & Temperature

A respectable performance from the ROG Ryujin II. Let's hop into the numbers and see how it's done when put up against the other pump solutions in the testing line up so far.

VRM Surface Temperature

Similar to the Arctic Freezer II we tested not too long ago, the Ryujin II has a VRM fan. In short, a VRM fans job is to help move hot, pooling air away from the VRM or "Voltage Regulator Modules" located around the perimeter of the CPU socket in most cases. Something like a tower air cooler already has a fan very close to this area, but an AIO has its active cooling somewhere far away bolted to the side of the case. AIO manufactures have started adding very small fans on top or around their pumps to return some active cooling back to this area. The Ryujin II is in line with the Arctic Freezer here, which actually had a much smaller fan. It is still a nice feature to have but the noise that comes with it you could certainly do without. Unless you're going for an extreme overclock this kind of temperature difference won't see you have any kind of performance gain. If I was considering a cooler for my PC, I'd probably opt for a different solution over a small, screaming fan.

VRM Surface Temperature Idle


VRM Surface Temperature Under Load


Here is the comparison graph which lists the Arctic Freezer II VRM surface temperature and the rest of our tested coolers. As stated this is the surface temperature of the VRMs.

Benchmarking Temperatures

Below is the important stuff, our three CPU benchmarks. These temperatures are not what you'll see on the screen, but a delta over ambient temperature, so don't expect your processor to be this cool! Still, the overall temperature we experienced was very good, you generally can't go wrong with this design. It's surprisingly the first Asetek pump design in this list and as expected it handles itself quite well. We didn't expect this cooler to beat out the Arctic Freezer II we've previously tested due to the thickness of the radiator. But if you want to see this comparison you'll find it at the end of this article.

Compatibility & Ease of Use

Fancy screens and proprietary software generally don't mix well with compatibility, which in all fairness is to be expected. The included controller with the ROG Ryujin II is required to make everything work. The pump and screen has 2 connectors, a micro USB and a USB 2 internal header. The internal header is for screen and fan communication, and the micro USB connects directly to the hub, which then requires SATA power to turn on. It is a little laborious, but a much better solution to the likes of Corsair, with a proprietary hub that isn't a standard form factor for any chassis, a large ribbon style connector that makes installation a fuss. The ROG controller is the size of a 2.5" storage device but just a little bit thicker and has 4 screw holes to mount in SSD or HDD trays. It also has double sided tape if you do not have a bay to screw it into. Because its a solid metal design we'd recommend screwing it down where possible because of its weight. Although the required controller isn't ideal. At least the connectors it has on it are all "normal". Standard 4-pin PWM fan headers and 3-pin 5v ARGB headers throughout. The big bulk of a screen does come off for installation and has a very satisfying magnet to hold it in place on its gold contact pads. With the screen on you'd have a hard time actually screwing the cold plate down, especially on an AM4 platform such as ours, but hey, at least its removal.
Removal screen showcasing the VRM fan and gold contact pads

CPU Socket Mounting

The block mounting was fairly straight forward and didn't need anything silly. It is a classis Asetek style mount with replaceable socket mounting holes by twisting a full plate off the bottom of the block itself. I really like this design, it's been used for a while but if it ain't broke, don't fix it. It allows you to rotate the mount whichever way you see fit. For instance, I rotated it to have the screen horizontal, and the tubes on the bottom of the block as seen here.
The screen will need removing to screw the block down, put you can just lift it off with your hands. The mounting for AM4 utilised the default backplate, which means it is also AM5 compatible, some third party standoffs were all that was needed for motherboard preparation.


The ROG Ryujin 240 strives to place itself at the top for aesthetics. Competing with the likes of NZXT, MSI and Corsair for the flagship features. The quality and size of the screen is great, you could spend a lot of time tinkering with this to make the theme work for your build, it makes it not just nice to look at, but engaging, a solid for user experience. I'll always appreciate it's not just for looks and has a function underneath all of that screen. Just whacking on an OLED, making a block twice as tall and upping the price tag would not be good enough.
The radiator itself is a very familiar design, likely from a family of Asetek products. People rarely care about the shape or style of a radiator other than the colour, but, having seen this shape for many years it does come across a little dated. A very mute point but one we'd like to make nonetheless. Other than shape, the radiator has the ROG stamped into the side which is a stylish touch.
When it comes to fans on the Noctua collaboration model we have, you could say "Yeah, those are just black fans... Right?" and well, you wouldn't be wrong. But if you've ever taken the time to look at a Noctua fan, the details compared to your Corsair or even Asus' own, you'll appreciate the work that has gone into making this fan one of the best performers on the market. From the stepped circumference leading to the blade and all the cut outs and angles, it is beautiful in its own right. We've included an image below that showcases some small dimples and fins for your viewing pleasure.
Asus has even put thought into the things you probably won't even see, such as the A-RGB/Fan controller. It is a solid metal design with some tasteful logos in the corner. I can say with confidence this is the nicest controller I've held, even if that is completely pointless.


First turning the Ryujin II on, the obvious tone of a fast spinning VRM fan is apparent. It is a noticeably louder unit that others we've testing. It's quite ironic due to the fact it's paired with very quiet Noctua fans, which you'd never hear over the drone coming off the CPU block. As expected from initial reactions, this is a louder cooler than others measured. A decibel (dB) reading is taken from 200mm away from the fans (intake) with no obstruction when idle and when under load, as well as *200mm from behind the radiator. *Approximated inside system, not always possible to get 200mm exactly.

200mm in front of radiator fans (Idle) - 31.7 dB

200mm behind radiator (Idle) - 40.1 dB

200mm in front of radiator fans (Load) - 56.0 dB 200mm behind radiator (Load) - 61.0 dB

Usability & Software

For those who don't know the name of Asus' all in one software, it's called Armory Crate, it has some very useful features such as automatically keeping important drivers up to date, and giving temperature or clock speed information for your processor. When it comes to the customisation options and overall usability of Armory Crate, one word comes to mind, shambolic. Plagued with loading screens if you switch tabs, and a lack of anything substantial for built in customisation leaves a bit of an empty experience. Something Corsair does do quite well is the customisation within iCUE, even if it can have a mixed bag of issues. You at least have the ability to upload your own media to make good use of that large screen. However, I don't think 3 pre-set images and a text box is good enough when spending this much for what is your primary feature.


We really like the look of this cooler, but struggle to get around the cost. The actual cooling hardware underneath isn't claiming to be anything special or unique and it relies on the CPU block design and fans from Noctua to carry it the extra mile. Credit where credit is due it does look fantastic, it is a shame the built in customisation options are rubbish in comparison to other brands, Armory Crate as a whole isn't that amazing, we're not a fan of them putting all of its eggs in the Armory Crate basket and feel it needs a lot of improvement.
Going into the review it was half expected to be a reverse of our Arctic Freezer II conclusion, aesthetically pleasing but performance not all there. However, it's done a find job on the cooling aspect of a cooler as well, but based off our usability experience, it wouldn't wow us enough to spend £239.99. As always, here is our final comparison graph for the temperatures of each cooler we've tested. This graph automatically updates when new coolers are reviewed, so don't forgot to come back and check it again.