Scythe S-FLEX (SFF21E)
One of the leaders in the air-cooling segment, the Japanese Scythe Company, is represented by five different fan models in our today’s roundup. Three of them are brand new solutions, while the other two should already be familiar to you from our previous articles, so we simply added them to the test session. The first model we will talk about belongs to the S-FLEX series. We got only one fan like that without the appropriate package and accessories. The official company web-site has some pictures of the S-FLEX fans packaging. They come in clear plastic blisters with cardboard inserts:
These fans are made in China and are priced relatively high: at $19.99.
Scythe S-FLEX fans looks quite common. I would even say that they look very unpretentious and even too simple. Matt black frame and black fan blades, that’s all it is:
The fan measures 120x120x25 mm, the weight is not specified. Each fan has 7 blades and a rotor 48 mm in diameter. Four oval-shaped rods hold the motor and fan blades. The smallest diameter of all rods is 4 mm except for one that has three-pin cable hidden inside:
S-FLEX fan lineup includes four fan models with rotation speeds ranging from 800 to 1900 RPM. We managed to get our hands on SFF21E model working at 1200 RPM that creates 49 CFM airflow. As usual, Scythe doesn’t mention the fans static pressure anywhere in the specs, considering this parameter to be secondary. The level of noise generated by this particular fan model shouldn’t exceed 20.1 dBA.
The blades curve slightly and have rounded edges. The gap between the tip of the blade and the inside surface of the fan frame doesn’t exceed 2 mm. I noticed that the fan rotor is of pretty big size. It seems that S-FLEX won’t be able to create a significant airflow.
However, these fans do have one peculiarity about them. It hides in the center of the fan. I am talking about the S-FDB bearing that stands for SONY Fluid Dynamic Bearing. As you may have already guessed, this bearing is developed by a well-known Japanese corporation, so only complete skeptics or those who have been plain unlucky with SONY products could doubt the high quality and extensive lifespan of this bearing. This is what its internal structure looks like:
It is a sleeve bearing with the bush sitting inside the metal ring that prevents it from drying out. We you understand, this bush will last way longer being permanently oil-lubricated. Moreover, there is an additional rotor suction magnet built-in to ensure better rotor centering. The motor is regulated by brand name Linear Drive controller. All this allowed the engineers to significantly lower the level of generated noise and reach the claimed 150,000 hours of fault-free fan operation (I wonder if anyone has ever checked that out?).
This fan should be pretty energy-efficient, because its claimed peak power consumption shouldn’t exceed 1.8 W at 0.15 A current. This Scythe S-FLEX fan model is declared to startup at 4.5 V max.
Since we do not expect Scythe S-FLEX to impress us with its airflow readings, the most interesting part of our test session will be the noise level. How did the use of S-FDB bearings pay back? Let’s find out:
I am telling you, S-FDB proved totally worth it! Scythe S-FLEX fan turned out one of the quietest fans of our today’s test session. Up to 1000 RPM this fan works in acoustically comfortable range for a mainstream user. You can’t hear its bearing in the entire operational range. However, despite the fact that there are only seven blades on a rotor of bigger diameter, this fan creates good airflow that yields just slightly to the leaders of our today’s test session. What an excellent fan! Extremely low power consumption and only 4.8 V startup voltage. Please, send me the entire S-FLEX series now! :)