Scythe Mugen 5 Rev.B CPU Cooler Review

Scythe's Mugen 5 Rev.B is one of the best CPU air coolers we have reviewed in recent times. Why? Come and find out.

Manufacturer: Scythe
13 minutes & 57 seconds read time
TweakTown's Rating: 97%
TweakTown award

The Bottom Line

Performance is impressive, noise is kept at bay, aesthetics are pleasing, it's affordable, and it now supports AM4 right out of the box. The Scythe Mugen 5 Rev.B has proven itself worthy for anyone looking for a new CPU air cooler!

Introduction, Specifications, and Pricing

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When it comes to shopping for a new CPU air cooler, Scythe will deliver three things, every time, no matter what. The first of those things is that no matter your needs in cooling or the space allowed for it to fit into, Scythe has one, if not two coolers to fit exactly what you are looking for. The second of these things is that when it comes to design and aesthetics, Scythe delivers some of the best-looking coolers available. The last thing, and what is most important to buyers today, is that you are given terrific performance results, with little to no audible noise coming from their products.

We also know that Scythe does not jump around with product lines, trying new things out of left field, hoping to hit a home run. Typically, their methodology revolves around delivering an updated cooler to an already existing product line, by absorbing customer feedback, as well as adapting existing designs to fit the needs of the users as the market evolves. Today is no different, as we delve into a cooler which sports a name that anyone will recognize, yet it has been adapted to fit the needs and requirements of motherboards which were not even though of when this cooler series was originally released.

As we sit here today, we are bringing forth the Scythe Mugen 5 Rev.B CPU cooler for examination. Based off the highly awarded Mugen 5, this latest version offers a few minor changes which will deliver customers flexibility, as well as accommodating the latest motherboards to be released. The Mugen 5 Rev.B has an offset and has a section removed from the fins to work flawlessly with motherboards supporting RAM on both sides of the cooler. More importantly, to AMD users, the cooler also brings new hardware to fit on AM4 motherboards. Scythe also uses nickel plating to the heat pipes and is using a new fan from their Kaze Flex series, to up the performance, without drowning you with noise. Realistically, bottom line, this is the Mugen 5 with new mounting hardware.

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In the chart taken from the product page, we find lots of information to discuss the Mugen 5 Rev.B CPU cooler. First of all, the Mugen 5 Rev.B can also be found by looking up the model number SCMG-5100, and we also see compatibility is quite encompassing. On the Intel side of mounting, everything since and including LGA775 is covered. As for AMD, the mounting hardware allows anything since and including AM2, all the way through to AM4 to have no issues with mounting either. Dimensionally, the Mugen 5 Rev.B is 130mm wide; it is 154.5mm tall, it is 110mm thick with the fan included and weighs in at 890 grams. The materials used are aluminum for the thirty-nine fins in the stack, as well as being used for the pre-cooler on the base. Copper is used for the heat pipes and is also used for the contact plate of the base, but both the pipes and the base are plated with nickel for looks as well as anti-corrosive reasons.

The fan of choice to cool this tower is the Kaze Flex 120 PWM fan or the SU1225FD12M-CHP fan. Dimensionally the fan is 120mm square, and it is 27mm in thickness, with a noise rating topping out at 24.9 dBA. Airflow is not amazing at just 51.17CFM, and neither is the air pressure with its 1.05 mmH2O rating. Fan speeds can range from 300 to 1200 RPM via PWM, and the hub spins on a Fluid Dynamic Bearing which is sealed, sporting a run time of up to 120,000 hours.

As we write this review, finding the cooler is somewhat a bit of a gamble. While we see many listings for the Mugen 5 and prices to go along with it, you need to pay particular attention to the model number. Many you will see listed when searching "Scythe Mugen 5 Rev.B" come back to the original, sporting the SCMG-5000 model number. However, even the one place, Coolerguys, who do list the correct model number, do not show the correct image for the hardware. We do know from the press release, that the €40 price overseas was not to have changed for the revision, so the $51.95 price shown there is roughly $5 over the transfer rate.

Currently, unless you had the Mugen 5 and got with Scythe support for the new brackets, this is the only place we found with the Mugen 5 Rev.B in stock on this side of the pond. While there is a touch of a price hike, if you have to have this cooler, you are going to have to meet their demands at Coolerguys.


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The front of the packaging is done in matte black, which allows the image of the cooler and the Scythe name and logo to pop. At the bottom, we see the notation to AM4 compatibility, we are shown the new name, and are also looking at an archer on horseback.

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The next panel on the box is where Scythe delivers the name of the product along with five, dimensional renderings, of the tower and the fan. At the bottom, some of this information is repeated, but they do go into further detail in the specifications shown in the chart.

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The back of the packaging is where we find where to go for support, as well as reading that outside of Japan; this cooler carries a two-year warranty. Along the bottom, we find precautionary notes and safety tips.

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The last panel shows off the key features. There is the asymmetrical design which allows for RAM clearance, and also a mention of the use of the Kaze Flex 120 PWM fan. Scythe then brings up the Hyper Precision Mounting System II used with the cooler and makes sure to tell us that this design is capable of using a pair of fans, although only one comes with the Mugen 5 Rev.B.

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Inside of the box, there is minimal packaging for the cooler. A thin layer of dense foam wraps the cooler like a taco shell, the fan sits on top of the foam, and the hardware rests on the fan. However simple the packaging may be, with a very long trip to our lab for testing, the Mugen 5 Rev.B came to us in perfect condition.

Scythe Mugen 5 Rev.B CPU Cooler

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So far, everything about the Mugen 5 Rev.B is identical to the original. There are thirty-nine fins, with the top one thicker than the rest, and caps over the heat pipe tips. The pipes are offset through the tower and have gentle curves as they enter either side of the base.

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Looking at what we could call the top of the cooler, once it is installed, we can plainly see the asymmetric design of this tower. The pipes are bent to allow the tower to sit back from its center point, leaving room for the primary fan placement, which is on the left of the tower, in this image.

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From the back, the look of the tower does not differ much from what we saw looking at the front. Different pipes are now visible due to the way that they are bent to run through the tower, but otherwise, there is nothing new to discuss.

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The same can be said for the side, but there is one thing we left out of our last look from a similar angle. Not only is the tower offset to remove conflict with RAM in front of it, at the back, but the lower five fins have also been cut short. This allows for RAM clearance behind it, for motherboards using quad channel memory.

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The top of the Scythe Mugen 5 Rev.B is nice to look at. Exposed natural aluminum fins with the Scythe logo embossed in it, the caps on the heat pipes, all of it looks nice and clean. There is an offset at the front and back edges which allows for space between the fan and the cooler body, and there are also two holes that run through all of the fins to help with mounting.

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On top of the base, Scythe uses a thick chunk of aluminum, which has fins in it to help dissipate some of the heat. Running across the fins is a mounting bar, which is permanently attached, and has the mounting screws built into the bar as well.

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All of the thirty-nine aluminum fins are pressed onto the heat pipes after the nickel coating was applied to them. The fit is tight, and when the holes were pressed, they have lips remaining, which helps to keep the fin spacing correct between each of the fins.

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The base of the cooler ships with a protective layer of plastic on it. This will help to keep the base in good condition, but as the warning says, peel this off before installation.

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The base is machined to a near perfect mirror finish. Any marks left from the machining of the base have been levels with the use of the nickel plating, and deviation of the surface only occurs nearest the edges. The mating surface is ever so slightly convex, which helps to increase pressure and helps with the removal of heat.

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Digging through the hardware, we grabbed a pair of the fan clips and installed the fan onto the tower. We see that the fan is nearly as wide as the tower, but it does push air above and below the tower.

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From the side, we see that the fan sits our just slightly further than the mounting hardware, which will cause no issues with the RAM in front of it. However, hanging a fan on the back will negate the clearance that the Mugen 5 Rev.B is notched to provide.

Accessories and Documentation

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On the left, we see a pair of brackets which are to be used for the various Intel mounts, all but LGA2011 and LGA2066. The back plate is universal to Intel usage, and the tabs have rubber pads to help isolates it from the motherboard. On the right is why this is the Mugen 5 Rev.B. The AMD brackets now have two holes at either end, allowing for the earlier location, and the newer AM4 location.

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In this image, we see the screws which mount the top brackets to either set of standoffs to the right. The first set next to the screws are the universal Intel standoffs, and the ones to the right are used for direct socket mounting, like that of LGA2011.

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When it comes to mounting this cooler to an AMD motherboard, you will need to use the set of long screws on the right, as well as using the black plastic spacers to ensure the top brackets can be used at the proper height. As for the chunk of rubber backed with 3M tape, that is a LGA775 pre-load spacer which can be stuck to the backplate.

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Universal to any mounting situation, we have this group of hardware. There are four wire fan clips sent along with the Mugen 5 Rev.B, as well as a short tube of thermal grease. Scythe also makes sure to send along a stubby handled screwdriver, as the only way to mount the cooler to the hardware, is to have the proper length screwdriver to reach the screws, through the cooler fins.

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The fan that cools the tower is the SU1225FD12M-CHP 120mm PWM fan. The fan has rubber pads in each corner, on both sides of the fan, to ensure the fan does not vibrate against the fins. The frame is black, the eleven blades are gray, and the 4-pin PWM fan connection is at the end of the black braided sleeve which covers the wire.

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The manual is typical for a Scythe cooler. It is multilingual, which reduces the amount of information provided in text form. However, with the parts list and the well-drawn renderings of the steps to install the Mugen 5 Rev.B, there should be no confusion or hassles when it comes time for you to install it.

Installation and Finished Product

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With three holes on each tab of the backplate, when properly aligned with the holes in the motherboard, the plate is crooked. Both sides of the plate are designed to fit, with larger holes than are needed for the pair of socket screws, and a wide gap at the opposite end to miss the third screw.

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To mount the backplate, we had to use the universal standoffs to do that. The tops of the standoffs are threaded to accept a screw, which is how we can secure the top brackets onto the standoffs. Be sure to put the brackets on either side, as the cross bar on the base of the cooler aligns this way to achieve the RAM clearance it is designed for.

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One we removed the protective layer from the base of the cooler, applied some thermal grease, and set the cooler onto the CPU, all that is left is mounting it. To do this, you can slide the provided screwdriver into the holes in the fins, and access the screws on either side. Alternate the number of turns you make to each screw, which ensures the best mounting and spread of the TIM.

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Due to the design of this tower, the fan can sit lower than the tops of our memory. The Mugen 5 Rev.B is nearly as wide as the memory is, and is cooled with a 120mm fan enables Scythe to keep the height under 155mm.

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Close it is easy to see daylight through the gap between the RAM and the fan. While we cannot go much lower with the fan due to the mounting hardware, if it were possible, we would have no issues in accomplishing it. There is plenty of clearance for the typical systems used.

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Moving further away, we can see that the notch on the back of the cooler is well above the height of our RAM, and will allow for some pretty tall sticks to fit in quad channel motherboards. While there is room in this build for the optional second fan, it is easy to see how it will cause memory conflicts when memory is on both sides of the cooler.

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Our last look at the Mugen 5 Rev.B has it hanging from out motherboard at this time. The view of the top of the cooler is dressed up with the pipe caps, and the Scythe logo, but we also find that the fan blends in well with the motherboard. Even from this angle, we can see all of the memory, and for those who like access to their memory, this cooler is about as good as it gets.

Test System Setup, Thermal Tests, and Noise Results

Chad's CPU Cooler Test System Specifications

To see our testing methodology and to find out what goes into making our charts, please refer to our CPU Cooler Testing and Methodology article (October 2016) for more information.

Thermal Results

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Allowing the PWM controls to do their thing, our stock test runs on this cooler has the Mugen 5 Rev.B able to deliver a result of 56 degrees. While the chart appears to not favor that result, keep in mind that it runs neck and neck with the NZXT Kraken X52 while was in performance mode.

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Still allowing for PWM control of the fan, the overclocked results chart tends to show the Scythe cooler in a better light. Sixth place overall at 70.75 degrees is quite the feat and stands near the top in some great company.

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Looking for the most the Mugen 5 Rev.B can deliver, we see that the PWM curve set for the fan is nearly top of the range. Forcing the fan to run on 12V shows us that we can only gain half a degree improvement, which means Scythe did a near perfect job with the setup and development of this tower and fan combination.

Noise Level Results

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At all time, we found the fan of this cooler to idle at 400 RPM, with little more than a slight "whir" heard when you are right on top of the fan. From a foot away, while the fan topped at 637 RPM for this reading, we only saw 25 dB on the meter at that time.

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When we took this 28dB rating during the PWM controlled overclocked run, we saw the fan spinning at 806 RPM. So far, with both tests, the noise level is under control and leaves the Mugen 5 Rev.B at the top half of the charts.

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The 30dB result when forcing 12V through the fan is the best we have seen so far. What is strange about this, not so much for noise, but spinning now at 1084 RPM, we would have expected slightly better performance than just half a degree of difference.

Final Thoughts

Sadly, we never did get our hands-on the original Scythe Mugen 5, but with only one difference in the coolers, we feel it would have to perform spot on to what we saw here today. As we looked to compare, we see that the Mugen 5 is now retired, but those who own them can apply for the new set of AMD brackets, which are what defines the Mugen 5 Rev.B from its predecessor. Since there is a lot of a following and much hype to go with everything new at AMD, it was a wise decision for Scythe to make a move. They have always been known for great cooling capabilities, so why limit your market, when you can re-engineer some bits and take the market on again. Either way, you look at it, Scythe has delivered us a solid cooler that is easy to use and can keep up with many coolers larger or more expensive, all without crowding components or breaking the bank.

The Mugen 5 Rev.B is nice to look at, and Scythe took the tip to cap the pipe tips, emboss fins with their logo, and deliver us a product which ticks all the boxes in all of the categories. The hardware has been updated to include AM4 users now, but whatever the system you chose to mount this cooler too, it couldn't be easier to do. Everything you need to get underway is included in the box, even clips to add a second fan.

This does lead us to the one downfall we found with the design though. If you plan to use the second fan, but use quad channel memory, you may run into issues with fitment of the fan over the memory. This negates the design quite a bit, and the hassle for a couple of degrees of improvement may not be worth it. Considering the Mugen 5 Rev.B did as well as it has, we honestly see no reason to want more from this cooler. The performance is admirable for it being a 120mm fan based cooler, and the noise levels are under control. Why screw with something which already does well as it sits?

What will also help many gravitate to this cooler, AM4 users or not, is the affordable pricing. While the stock is limited currently to only one location, with a slightly premium asking price that breaks the $50 mark, this isn't how it should be. Since all of the press noted that the price would not change from the original design, we expect that when Amazon and Newegg pick this cooler up, you will find a price much closer to or slightly less than $45.

With everything we have seen in the feature set, with the performance results all gone through, and with the cost what it is, it is hard to deny Scythe their dues as the Mugen 5 Rev.B is an understated, possibly underestimated, competition killer.

TweakTown award
Performance 94%
Quality 97%
Features 98%
Value 98%
Overall 97%

The Bottom Line: Performance is impressive, noise is kept at bay, aesthetics are pleasing, it's affordable, and it now supports AM4 right out of the box. The Scythe Mugen 5 Rev.B has proven itself worthy for anyone looking for a new CPU air cooler!

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Chad joined the TweakTown team in 2009 and has since reviewed 100s of new techy items. After a year of gaming, Chad caught the OC bug. With overclocking comes the need for better cooling, and Chad has had many air and water setups. With a few years of abusing computer parts, he decided to take his chances and try to get a review job. As an avid overclocker, Chad is always looking for the next leg up in RAM and coolers.

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