Scythe Fuma 3 – A pair of counter-rotating impellers

Pavel Sekerka

1 year ago

Key features

Another cooler that we will have time to look at this year is the Scythe Fuma 3. This cooler uses several atypical design elements, which makes it different from the usual dual-tower coolers in its class. Moreover, with a price tag of just over 50 EUR, it could offer an interesting price/performance ratio. Additionally, this is my first experience with a Scythe cooler, so I’m also duly curious to see how the Fuma 3 performs in stress tests.

Key features of the cooler

Scythe Fuma 3 is a really interesting cooler. It is a highly asymmetrical dual-tower cooler that uses two completely different types of fans. While the rear tower hosts a classic 25mm fan from the Kaze Flex II series, the front tower, which is also relatively thin, hosts a 15mm slim fan. To make things even more interesting, the two fans rotate in opposite directions to each other, which can have an impact on both the acoustics and of course the overall efficiency.

So the front tower is really thin and it is also noticeably offset towards the centre of the cooler in order to, in combination with the slim fan, ensure maximum compatibility with RAM modules on the motherboard. The rear tower, on the other hand, is quite large and has a cutout at the bottom to avoid physical conflict with a passive power cascade cooler on the motherboard. In addition, another (third overall) fan can be mounted on the rear tower, whose usefulness will be verified in a future article.

The two towers are connected by six 6 mm diameter copper heatpipes with a nickel-plated surface. The large copper base through which these heatpipes pass is also treated with a layer of nickel and polished to a mirror shine. The upper surfaces of both heatsink towers feature a decorative cover with a very minimalist manufacturer’s logo. On the front tower, you can notice a pair of small cut-outs from above, which serve as a path for a screwdriver when installing the cooler.

The manufacturer is very generous with the accessories supplied with the Scythe Fuma 3 cooler and there is nothing important missing. The mounting system of the cooler is sufficiently robust and of appropriate quality. A very nice bonus is the handy long shank screwdriver for the easiest possible installation of the cooler. You will also find a tube of thermal paste in the package, including a small plastic applicator. There is also a splitter for connecting both supplied fans to a single PWM header on the motherboard. You will also find an additional set of clips for attaching a third fan to the back of the cooler. The accessories are then rounded off with a clear and well-designed manual.

The installation of the cooler is simple and straightforward, so you shouldn’t encounter any setbacks. Just make sure to choose the correct spacers according to the socket (LGA 1700 socket has its own set) and adjust the spacing of the screws on the supplied backplate in case of mounting on an Intel processor. During installation, you also have to remove the middle 120mm fan for a while and at this point you will fully appreciate the supplied screwdriver.

Cooler and fan parameters

Scythe Fuma 3 does not stand out from its class of coolers in terms of dimensions. A positive element is its overall height, which is just under 155 mm, which is sometimes the limit of compatibility of some smaller cases (for example, the popular Masterbox NR200P from CoolerMaster), without somehow reducing the overall density of the cooler or interfering with the compatibility with the RAM slots on the motherboard.


Cooler	Scythe Fuma 3	SPC Fortis 5 Dual Fan	DeepCool AK400 ZDP
	DeepCool Assassin III		DeepCool AK400 ZDP
Supported sockets	Intel LGA 115x, 1200, 1700, 20xx; AMD AM4/AM5		Intel LGA 115x, 1200, 1700, 20xx; AMD AM4/AM5
Height	154 mm	159 mm	155 mm
Width	138 mm	144 mm	127 mm
Depth with fan	128 mm	131 mm	123 mm
Weight	1095 g	890 g	802 g
Maximum RAM height	no restrictions
MSRP	€ 53.00	€ 48.50	€ 52.90

/* Here you can add custom CSS for the current table */ /* Lean more about CSS: https://en.wikipedia.org/wiki/Cascading_Style_Sheets */ /* To prevent the use of styles to other tables use "#supsystic-table-2771" as a base selector for example: #supsystic-table-2771 { ... } #supsystic-table-2771 tbody { ... } #supsystic-table-2771 tbody tr { ... } */

As mentioned, the Scythe Fuma 3 uses not only the asymmetrical heatsink design, but also an atypical fan configuration. On the front tower you will find the Scythe Kaze Flex II 120 PWM Slim, which is a 15mm thick fan, and on the rear tower you will find the classic Kaze Flex II 120 PWM. The static pressure and airflow values for these fans are not very high though, so hopefully the manufacturer knew what they were doing and these fans will be efficient enough in combination with the heatsink of the cooler over the entire speed range.


Fan	Kaze Flex II 120/120 Slim	Fluctus 140 OS PWM	DeepCool FC120P
	Fluctus 140 OS PWM	Fluctus 120 L PWM	Fluctus 140 ARGB PWM
Bearing	FDB
Max. speed	300–1500 rpm	300–1400 rpm	500–1650 rpm
Max. airflow	114.9/67.0 m³/hod	N/A	101.0 m³/hod
Max. static pressure	1.50/0.96 mm H₂O	N/A	1.62 mm H2O

/* Here you can add custom CSS for the current table */ /* Lean more about CSS: https://en.wikipedia.org/wiki/Cascading_Style_Sheets */ /* To prevent the use of styles to other tables use "#supsystic-table-2772" as a base selector for example: #supsystic-table-2772 { ... } #supsystic-table-2772 tbody { ... } #supsystic-table-2772 tbody tr { ... } */

Testing methodology

As a test processor and heat generator I use the Intel Core i7-11700K on the Asus TUF Gaming Z590-Plus WIFI motherboard. The entire build is mounted on a Streacom BC1 frame with no fans to provide airflow. Acoustic shielding (acoustic foam on OSB boards) is installed around the test rig to eliminate ambient noise. The Voltcraft SL-100 calibrated noise meter is placed perpendicular to the cooler in a fixed position relative to the motherboard at a distance of approximately 35 cm from the processor socket.

Stress tests are performed using Prime95 with a duration of 30-35 minutes. Coolers are tested at three standardized noise levels (36, 39 and 42 dBA) and then at maximum speed. In addition, I am gradually adding tests at 45 and 48 dBA levels and you will also find this data in the results over time. The tests are run in two sets based on the thermal output of the processor.

The first set of tests is at 125 W, i.e. the forced PL1 limit of the processor. In the second set, the power draw is then about 210 W (4500 MHz at 1.285 V). However, this second level represents a very high concentration of heat per mm2 due to the small size of the chip itself. Thus, not all coolers can be expected to pass this set of tests at all noise levels. For example, no cooler has reached the 36 dBA level at this load, and I ended up eliminating it from the tests after some consideration.

The highest temperature reached after the test is always recorded. All data regarding temperatures and thermal output of the processor are obtained from HWiNFO64. The measured values are then adjusted against the temperature in the room as the resulting Delta T. The test success limit is set to 75 °C. Any higher value means a risk of processor temperature above 95-100 °C and a risk of thermal throttling. Therefore, if the cooler does not pass the load with a Delta T value below 75 °C, such a test is marked as a failure.

Results – 36 dBA

Unfortunately, I was again unable to get results at 36 dBA. The fault lies with the motor, which makes a quiet, but not inaudible, clacking noise at low speeds. Thus, the lowest noise level for this cooler was just under 37 dBA.

Why is there a missing value in the cooler chart? Either because the cooler could no longer handle the load in the specified mode, or because the fan could not be slowed down to the required level, typically the mode with the lowest noise level.

Results – 39 dBA

Results – 42 dBA

Results – 45; 48 and 51 dBA

For the next calendar year I am already planning to expand the values to 45 and 48 dBA, but for now I am attaching a simple graph of the dependence of Delta T on noise for this cooler in different fan configurations. I also ran tests with a total of four different fan configurations, for now I will only present the results for the “Default” and “Single Fan” variants (without front fan). In any case, the graph clearly shows that the front fan has its irreplaceable function and removing it sharply decreases the overall efficiency of the cooler.

Results – maximum speed

Spectral analysis of noise

This is a simple analysis at noise levels of 39 dBA, 45 dBA and at maximum speed of the cooler. For the analysis I use the UMIK-1 microphone from miniDPS in conjunction with True Audio’s TrueRTA application. The resolution of the analysis is 1/24 of an octave and the shape of the spectrogram is an average of 100 samples acquired over 20–30 seconds.

Conclusion and evaluation

I admit that I am a bit disappointed with the results of the Scythe Fuma 3 cooler and I expected more. At maximum speed the cooler does achieve slightly above average results, but when the speed drops somewhere below 50% its efficiency drops sharply.

I repeated the tests several times and also checked the mounting for sufficient pressure on the processor to eliminate the possibility of a wrong measurement, but unfortunately the results were always the same. It’s a shame, because the cooler is otherwise very well made, its size and shape pose no compatibility issues for the vast majority of builds, and its price tag is also still in the range of affordable coolers.

Scythe Fuma 3 unfortunately fits into the grey average of coolers. Personally, I would not recommend it for processors with high heat output, so Intel i7 or i9 series processors are practically out of the question. However, for regular builds with mid-range Intel processors without an unlocked multiplier or for AMD Ryzen processors except for the highest end models, it will easily suffice.

English translation and edit by Jozef Dudáš


Scythe Fuma 3
+ Interesting cooler design
+ High build quality
+ Generous accessories
- Only average results
- Fans clacking at low speeds
- Low price/performance ratio

/* Here you can add custom CSS for the current table */ /* Lean more about CSS: https://en.wikipedia.org/wiki/Cascading_Style_Sheets */ /* To prevent the use of styles to other tables use "#supsystic-table-2773" as a base selector for example: #supsystic-table-2773 { ... } #supsystic-table-2773 tbody { ... } #supsystic-table-2773 tbody tr { ... } */

Continue: Measurement methodology