A Closer Look at the Scythe Ninja 4
Standing 155mm tall, the Scythe Ninja 4 is not a small heatsink by any standard. Without a fan installed it is 130mm wide and symmetrical so all sides have the exact same width and height. The Scythe Ninja 4 has also streamlined the “ninja” theme by making the fin resemble a shuriken front top looking down unlike the previous generation Ninja 3 Rev. B which looked more like a hot rod engine stack complete with flames. While the middle part is now connected, there are still gaps halfway from the edge which also functionally help easy installation as a long screw driver (such as the one bundled) can be passed through to secure the mounting bar onto the mounting plate.
There are 36-fins in total and as is obvious from the photos, have a high-quality reflective finish. Unlike the Ninja 3 Rev. B which had independent aluminum fin stacks, the Scythe Ninja 4 revised their multi-airflow pass-through structure to be connected at the center and if you look closely at the middle, criss-cross alternatingly to accelerate and distribute airflow much more efficiently across. There are six 6mm heatpipes in a U-shaped formation and these distribute evenly in four groups of three toward each corner. Unlike the Ninja 3, the Scythe Ninja 4 copper heatpipes are fully nickel plated to combat oxidation.
You can look all you want at the top of the heatsink but you can only truly judge a heatsink’s build quality by looking at how the heatpipes are connected at the base. Scythe did a stellar job with this and it is remarkable how clean and neatly tidied it is. The contact surface itself measures 38 x 43mm with the longer side on the heatpipe row. For reference, Intel’s HEDT LGA2011 CPUs have a 38×38 integrated heatsink surface area.
Like the copper heatpipes, the copper base is also nickel plated and is highly reflective with a center apex. Looking closely reveals discernible machining marks across and circular.
The bundled fan is a 120mm Scythe GlideStream 120 PWM SY1225HB1212H-PS fan. This is a sleeve bearing fan so this is where concession was made to make it more affordable. The fan itself otherwise has very good specifications with up to 1.79 mmH²O static pressure at the 1500 RPM maximum. There are nine blades in total, each with a groove across the top surface for lessening air resistance and with only a 36mm diameter hub, the fan blades cover a bigger surface area. The blades themselves are wide with big gaps in the middle, able to scoop plenty of air even at low fan speeds. There are four struts on the exhaust side curving against the the blade curve. The frame is otherwise standard 25mm thick and conforms with typical 120mm fan form factors.
It is a PWM fan so the range is controllable but Scythe was considerate for non-PWM users as well by providing a switch on the fan that limits the fan speed to three levels: high (~1500 RPM max), medium (~1150 RPM max) and kow (~800 RPM max).
The fan cable is nicely sleeved and has a 4-pin connector, Readings from ASUS Fan Xpert II reveal the real-world controllable PWM range: