The way pulse width modulation (PWM) works in cooling devices is based on a premise similar to the thermostat. In the most common scenario of PWM control, power driven into your CPU cooler is adjusted depending on its temperature. An idle CPU does not generate as much heat, requires less active cooling, and hence slower fan speeds will be sufficient. Obviously, this also reduces the overall ambient noise and best of all, it's handled automatically with little risk to your PC components.
While this feature has become quite popular in the PC cooling solutions industry, with PWM supported fan headers (usually of the 4-pin variety) natively available on most motherboards, there is often only one or two of such headers, reserved for the CPU and/or chipset coolers. This means there's no way this excellent noise reduction idea can be extended to the numerous system fans inhabiting the typical chassis. This is exactly why Cooler Master has come up with its new PWM fan hub, the Wind Rider.
With an ability to work with up to six PWM fans (Cooler Master naturally has a new line of 80, 92 and 120mm PWM fans to market along with the Wind Rider), this fan hub takes in the PWM signal input from the motherboard and controls its posse of connected PWM fans for the optimal performance in noise and cooling. At least that's the theory.
In reality, the Wind Rider is a small and light box with a power connector and a slider at the sides that looks like a prop right out of an X-Men movie. Beneath the cheap plastic exterior though, there is a small circuit board with the various connectors for the fans. There are five signal outputs for up to five system fans and one reserved for the CPU fan.
Meanwhile, the single input connector accepts signals from the motherboard PWM header and uses the information to regulate the fan speeds for all the connected fans. For those motherboards with headers to monitor fan speed, you can attach the included fan signal cable to them.
The slider bar located at the side is an additional manual voltage adjustment to further control the fans, ranging from 6V to 11V; not that we can tell since there are no markings whatsoever (it's stated only in the manual). This is probably for cases where manual fan control is more desirable, such as an overclocking session. The Wind Rider has two status LEDs: A blue LED indicator to determine if the PWM signal cable is plugged into the motherboard and a red LED to indicate power. Installation is pretty straightforward once you've sorted out which of your fans you want controlled and with the included Velcro straps, you can attach the Wind Rider anywhere within the chassis.
To make full use of the Cooler Master Wind Rider PWM fan hub entails having a whole set of PWM capable system fans. While we don't doubt that such a system will regulate the noise and thermal environment within the chassis, it does add a fair bit of cables and extra work in managing them, not to mention that most users would only have up to three fans at most. The only other discomfort is since this gadget resides inside the chassis, the manual voltage slider isn't within ease of reach. In any case, Cooler Master's range of supporting PWM fans are a decent add-on and sure to work with the Wind Rider. Prices too should be rather inexpensive, since these accessories are relatively cheap to manufacture. Heavy users with multiple fans will probably be the ones who will appreciate having the Wind Rider consolidate all their fan controls into one box unit.
Prior to this fan nifty gadget, the only alternative is the traditional, manually controlled fan controller hub where some of the digitally controlled versions use other means such as a thermistor to monitor internal case temperatures to regulate fan speed needs. However, the Cooler Master Wind Rider PWM fan hub is probably a more accurate approach to controlling all your system fans timely in a more hands-off approach. For those who this approach, you will appreciate the Wind Rider PWM fan hub; however hardcore users might prefer the full control and feedback of the traditional fan controllers.