Build the Perfect Lab or Office Workstation

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Part 3

Cooling

Proper cooling is paramount for silent operation. Fans, at least in our case, are going to be operating within a certain RPM range; their speed depending on system temperature. If your system runs hot, the fans are going to have to spin faster, thus causing significantly more noise. Let’s now discuss some of the low-noise cooling methods.

Air circulation inside the chassis

The three main hot components, i.e., the power supply, the CPU, and the GPU will need their own, dedicated cooling. However, we also need to provide proper air circulation inside the chassis itself. Minimally, you need one intake and one exhaust chassis fan (see Figure 1). The idea is that cool air is sucked in from outside the case and moved over the hot components to be then sucked out of the case by the rear (or top) exhaust fan (Figure 1).


Figure 1. Typical airflow inside a computer chassis. The blue arrow indicates cool air, and the red one warm air.

The case cooling system can get very complex and sophisticated, with multiple fans of different diameter, operating at different rotational speeds. I have seen Dell, Apple, and HP workstations with additional air ducts inside the chassis, made by means of removable plastic chambers. The utility of such separate chambers remains somewhat debatable, but the general idea of trying to keep heat-generating components cool and maintaining proper air circulation inside the case applies across the vast majority of modern workstations. We must remember, though, that, Inevitably, the faster the fans spin, the louder they get.

Computer fans are typically described in terms of their diameter, rotational speed, their air moving capacity (measured in cubic feet per meter, or CFM), the noise level (measured in dB), and the connector type. For example, the Thermalright TY-140 fan that we’re going to use for the CPU and GPU is 140 mm in diameter, offers speeds of 900-1300 RPM, has CFM of 28.3~74, and the noise level of 17~21 dBA. The fan uses pulse width modulation (PWM) technology to adjust its speed depending on the temperature in its immediate environment.

There are many different types of chassis fans available so, and, unfortunately, the specifications provided by manufacturers cannot always be trusted. There exist no standard noise testing methodologies, so it is best to rely on independent reviewers, such as Silent PC Review, for a more standardized evaluation. I have had very good experience with Nexus, Scythe, and Gelid 120mm, PWM fans.

Some of the modern computer motherboards (though not as many as one would like) support the PWM technology and provide a BIOS-level monitoring and control of fan speeds. When selecting a motherboard, I typically pay close attention to whether or not it supports at least three PWM fan headers. Other methods of fan speed control involve the change in voltage (e.g., “undervolting” to 5 or 7 V, instead of the full 12 V), but I think PWM is the most straightforward and effective approach.

The BIOS-level PWM technology enables motherboard manufacturers (e.g., Intel) to write temperature management software for Windows. Such software provides an additional level of temperature monitoring and fan speed control, though it is not required to keep your system running cool and quiet. Finally, a dedicated hardware-based fan controller can be used, especially if one requires fully manual fan speed control. Fan controllers can be typically installed inside the 3.5” or 5.25” drive bay.

Theoretically, a medium-size, ATX chassis, such as the Antec P183 case I have chosen for the present build, should be adequately cooled with one or two intake fans and one exhaust fan, all controlled by the BIOS-level software. However, in order to facilitate good airflow, it is essential to keep the interior neat, tidy, and dust-free. Proper cable management will help, as well. Figure 2 illustrates airflow inside the Antec P183 V3 case. Note two thermal chambers; the top for the motherboard, CPU, and GPU, and the bottom for the power supply and hard drives.


Figure 2. Airflow inside the dual-chambered Antec P183 V3 workstation case


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