Page 2 - A Closer Look - Hardware
On the left side is the Fractal Design Venturi HP-12 PWM, and on the right is the Venturi HP-14 PWM. Inside the box of both of these fans are four metal screws, and a PWM Y-splitter cable. The HP-14 also comes with four additional rubber fan mounts, which allow you to mount this 140mm fan in a 120mm fan slot, as long as you have enough physical space around the vent. This is a great idea, as sometimes people have the room, but they do not have the actual mounting holes to place a 14cm fan. This allows users for more flexibility, and this is great to see.
Both of the fans are made in a similar black or dark-gray coloring scheme. This stealthy look makes the fans almost inconspicuous, and tries to blend into dark places like your computer. Past Fractal Design fans have employed a generally conservative coloring scheme, with white being the only other past color to be used. In fact, this follows quite closely in line with the other Fractal Design products we have seen in the past. Rather than trying to look flashy or add pizzazz, Fractal Design believes more in the performance of their products. When it comes to appearance, Fractal Design keeps a low-key and simple approach. The fan frame on both the HP-12 and HP-14 are also minimal in design, with only four arms obstructing any airflow. Unfortunately, the lack of any grille does mean you should watch your fingers when you are using these fans, as they may get nicked. The wires on the Venturi fans are 50cm in length, which should give you more than enough wire to work with, in both mid-tower or full-tower cases. In addition, they all come braided, which is a nice touch.
Even though these two fans are of different sizes, they share a lot of similar internals. Both use FDB or fluid dynamic bearings. Fractal Design refers to them as "true" FDB bearings, because the inner surface of the bearing is covered with two sections of herringbone groves. This is actually a patented design by Matsushita Electric Industrial Co., or now more commonly known as Panasonic. The grooves push oil along the grooves when the fan is in motion, which stabilizes the rotor, and results in longer lasting fans. The numbers do not lie, as both the HP-12 and HP-14 are rated to last 1,500,000 hours before failure, which is more than seventeen years. Other manufacturers, such as Noctua and SilverStone, also offer fans with this kind of lifespan, but with various bearings. Otherwise, the differences of the two fans are quite obviously the physical size. The HP-12 is 120 x 120 x 25 mm, while the HP-14 is 140 x 140 x 25mm.
As both the Fractal Design Venturi HP-12 PWM and HP-14 PWM are focused on higher pressure, you will notice the fins have a much larger width, with a greater overlap near the ends of the blades. In fact, looking at the Venturi HF series, you will notice those blades are quite thin and feature very little overlap. Those fans tend to generate greater airflow, while sacrificing static pressure. Both the Venturi HP-12 and HP-14 fans have seven wide blades, and offer similar characteristics between the two models. Fractal Design has also taken the liberty to introduce two small differences in their fans, which is said to make a big difference. First is what they call the trip-wire technology. This is seen in the slight protrusion seen on the edge of every blade. Commonly found on airplane wings, they are is meant to introduce turbulent air near the leading edge of the fan blade, to reduce or avoid any flow separation. In turn, this should reduce the drag experienced by the blades, and thus reduce fan noise and increase efficiency. The second design choice is three small notches found near the center of the fan on each blade. These are supposed to reduce the noise created when the fan passes the stator struts. Finally, Fractal Design has also employed fully rubber mounts on all corners of the fans. As there are no plastic parts at the mounting area, this should reduce the vibration between the fan and the case or heatsink it is mounted to.
These two fans, as indicated by their name, are both pulse-width modulation fans, or PWM fans. This means they use 4-pin headers and connect to most modern motherboards. As for rotational speeds, the HP-12 PWM runs from 400 to 1800 RPM, while the HP-14 PWM runs from 400 to 1500 RPM. On the topics of sound, airflow, and static pressure, the following lesson on these issues have been borrowed from Editor-in-Chief Jonathan Kwan's review of the Noctua NF-F12 PWM and NF-P12 PWM fans.
Noise and CFM relates to the big challenge when designing fans is to provide the best airflow to noise ratio. One would want the best amount of airflow, while keeping it as quiet as possible. Even with the best ratio, it is quite difficult to measure objectively at all times. The most common unit of objective measurement is CFM (Cubic feet per minute) of air for airflow, and dB noise, respectively. We will go over how application and CFM is related with regards to its standard measurements, but let us discuss perceived noise first.
dB (Decibels) is a logarithmic unit of sound intensity. While it provides what appears to be an objective measurement for the most part, it should be noted that perceived noise levels to the human ear, and actual sound intensity, could result in very different things. Human ears are more sensitive to particular frequencies, and when those particular frequencies are emitted from its source, it may appear louder than its numbers suggest. That same can be said vice-versa -- frequencies that human ears are less sensitive to can actually have louder dB measurements from a sound meter, yet the human ears does not perceive it to be as loud as the numbers suggest. Other factors such as turbulence noise are often not measured correctly, therefore, while it usually provides a good reference, it does not necessarily reflect real life performance.
With regards to the application and CFM, it is generally optimal to have a fan to have a high air volume flow rate -- but as aforementioned, pure CFM values are limited to an extent with regards to its indication on fan performance. It is not completely about how much air in can move per minute quantitatively, but equally as important is how it is executed in reality. Airflow to noise ratio is an essential factor as mentioned earlier. Static pressure is also very important depending on application. High resistance applications such as dense fins on a large heatsink require high static pressure, while case fans needs less static pressure and faster airflow. There are times where case fans will require higher static pressure too, such as the frontal intake fans, where a mesh grille would create some resistance. The differences in application is like a large truck that has a diesel engine with lots of low end torque for towing, compared to a sports car with a high revving gasoline engine with lots of power to beat around the track -- they are simply designed for different purposes, so choose one appropriate to your needs.
With all this out of the way, let's look at the technical detail of the fans. The Fractal Design Venturi HP-12 PWM is rated at 61.4 CFM, 31.7 dB, and 2.3 mmH2O. The Venturi HP-14 PWM is rated at 78.1 CFM, 30.1 dB and 1.94 mmH2O. By specifications, it would seem like the HP-14 PWM creates more air movement, while producing less noise, but this is understandable considering its larger size. However, we will see how this actually transfers into our classic performance tests, which looks at more than just the numbers.
Page Index
1. Introduction, Packaging, Specifications
2. A Closer Look - Hardware
3. Performance Tests
4. Conclusion
