Thermalright X-Silent 120: Quiet operation for a bargain

Thermalright X-Silent 120 in detail

Thermalright fans have been somewhat overshadowed by great heatsink throughout this company’s history. For a long time, even relatively high minimum speeds were awkward. These have now been tamed for most current models and the X-Silent 120 has a superbly low top speed as well. This is the “slowest” fan we have tested to date. With a price of under five euros, it also ranks among the cheapest you can buy.

At HWC though, we won’t deprive you of the analysis of Thermalright fans, which are among the elite in cooling products. We’ll go through all the relevant models one by one, but we’ll start with the simpler X-Silent 120 fan. Although this is a discontinued model, Thermalright still doesn’t have an adequate (low-end) replacement for it and some pieces are still in stock.

On sale, the X-Silent is priced between 3 USD (Ebay) and 10 USD (Amazon), for new, unused pieces, of course. For Slovak and Czech customers TN Trade has a rich stock of X-Silent for 4 EUR (100 CZK)/piece. So, considering the price, we don’t expect any miracles, and even the below-average features can be considered a bargain.

The rotor consists of fairly ordinary blades (with only an average curvature of the leading edge and an average width), which will certainly not break records in efficiency (this design has long been surpassed), but this is not expected from such a cheap fan.

The low price of the X-Silent 120 is reflected in the extremely low weight of 94 g. 120 mm fans with a full (25 mm) profile usually weigh from 120 grams upwards. Compared to other low-cost fans, the frame in particular is more delicate.

It’s not often that you can easily bend the corners of a frame on fans by exerting force between your thumb and index finger. Not even on the Arctic P12, which is a fan in the same price range. The blades are admittedly made of a fairly soft material, but where they need it most, they’re up to around 2mm thick, which is quite respectable. Specially considering that these are fairly short blades and the top speed (1000 rpm) is also quite low. Both of these factors minimize the effect of unwanted deformation (flattening) in flight.

The overall design of the fan matches how much it costs. Apart from the cheaper plastic, you won’t find anti-vibration washers here (instead, a set of rubber spikes is available alongside the self-tapping screws as one of the options for mounting the fans to the case), and the cable is plain as well. Although Thermalright didn’t skimp on it like Xigmatek did with the similar XLF-F1256. In contrast, the X-Silent 120 has individual wires in a common mesh (the XLF-F1256 only has them looped together). The three-pin connector at the end is both here and there, though. So the method of speed control is by changing the fixed voltage, linear (DC). The cable is otherwise quite long, at 40 cm. Included with the accessories is an adapter for the old Molex connector with a 5 V connection. This will cut the fan speed roughly in half (~520 rpm).

Traditionally, you can find a list of basic parameters in the chart below. The static pressure numbers are not listed by Thermalright. Maybe because its value would have to start with zero, which is not very appealing. But it is nothing to be ashamed of and the lower static pressure results from lower speed and under such conditions (at lower noise) it works out similarly for competing fans.

* When reading performance values, a certain amount of tolerance must always be taken into account. For maximum speeds, ±10 % is usually quoted, minimum speeds can vary considerably more from piece to piece, sometimes manufacturers will overlap by as much as ±50 %. This must then also be adequately taken into account for air flow, static pressure and noise levels. If only one value is given in a table entry, this means that it always refers to the situation at maximum speed, which is achieved at 12 V or 100 % PWM intensity. The manufacturer does not disclose the lower limit of the performance specifications in its materials in that case. The price in the last column is always approximate.

• Contents
• Thermalright X-Silent 120 in detail
• The basis of the methodology, the wind tunnel
• Mounting and vibration measurement
• Initial warm-up and speed recording
• Base 7 equal noise levels…
• .. and sound color (frequency characteristic)
• Static pressure measurement…
• … and airflow
• Everything changes with obstacles
• How we measure power draw and motor power
• Measuring the intensity (and power draw) of lighting
• Results: Speed
• Results: Airlow w/o obstacles
• Results: Airflow through a nylon filter
• Results: Airflow through a plastic filter
• Results: Airflow through a hexagonal grille
• Results: Airflow through a thinner radiator
• Results: Airflow through a thicker radiator
• Results: Static pressure w/o obstacles
• Results: Static pressure through a nylon filter
• Results: Static pressure through a plastic filter
• Results: Static pressure through a hexagonal grille
• Results: Static pressure through a thinner radiator
• Results: Static pressure through a thicker radiator
• Results: Static pressure, efficiency by orientation
• Reality vs. specifications
• Results: Frequency response of sound w/o obstacles
• Results: Frequency response of sound with a dust filter
• Results: Frequency response of sound with a hexagonal grille
• Results: Frequency response of sound with a radiator
• Results: Vibration, in total (3D vector length)
• Results: Vibration, X-axis
• Results: Vibration, Y-axis
• Results: Vibration, Z-axis
• Results: Power draw (and motor power)
• Results: Cooling performance per watt, airflow
• Results: Cooling performance per watt, static pressure
• Airflow per euro
• Static pressure per euro
• Results: Lighting – LED luminance and power draw
• Results: LED to motor power draw ratio
• Evaluation