Phenquestions
Raspberry Pi is widely known as a multi-purpose computer. It was developed initially to make computer learning and coding cheap and practical for students. Later on, it found popularity with DIY enthusiasts and project builders because it's low-cost, versatile, and compact. In almost a decade, the credit-sized board already spanned four generations, and the Raspberry Pi Foundation already sold more than 30 million boards.
Raspberry Pi's latest generation, the Raspberry Pi 4 B, is one powerful beast. Armed with a quad-core Broadcom CPU that clocks at 1.5GHz, a Broadcom GPU, up to 8GB of RAM, a Gigabit Ethernet, Wi-Fi, and Bluetooth, it's a Pi that can deliver a desktop-level performance. However, there is one downside to it - overheating.
Like its predecessors, Raspberry Pi 4 B does not contain a built-in ventilation system. It wasn't really a problem with the previous generations considering that their specs are lower. Passive cooling, like adding a heatsink, would usually keep the components cool. In most cases, it's not even necessary. However, with Raspberry Pi 4's specs, even a heatsink may not be enough if the Pi is used extensively and even more so if it's enclosed in a casing.
Keeping It Cool
Electronic products such as computers emit heat when used, and too much heat can be detrimental to the system. That's why we see cooling components such as fans and heatsinks inside our laptops and desktops.
Many are satisfied with Raspberry Pi 4's performance. Still, many have also noticed that the CPU throttles when used for an extended period or when the tiny board carries too much load, like when resource-intensive applications are being run. A test by one user shows that the CPU reached 80°C in just a matter of minutes when watching videos or scrolling through complex sites. Once it gets 80°C, the CPU starts to throttle.[1] It's the same case with the GPU once the temperature rises to 85°C. Thermal throttling significantly affects the Pi's performance; dropping the CPU's clock speed to as low as 750MHz from 1.5GHz slows down the processing time. Not only that, the whole board becomes too hot to handle because the other components heat up too.
Other tests are done by different users, indicating that Raspberry Pi 4 B's CPU throttles rapidly compromises its performance. To reduce or eliminate thermal throttling, it's best to integrate both a passive and an active cooling system with the Pi. If you keep the Pi in a casing, placing a heatsink on top of the CPU can help a little, but to have better airflow and prevent thermal throttling, it is best to install a fan. Better ventilation would keep the CPU and other board components from deteriorating, which lengthens the Pi's lifespan.
This would, however, also result in an additional expense on your PC set-up or projects, so buying a Pi would not be as cheap as it was before. The next question is, when do you really need a fan for RPi 4?
To Fan or Not to Fan?
The Raspberry Pi Foundation is well aware of the heat issue that RPi 4 B is experiencing; that's why they have issued a firmware update that would fix this issue. The new firmware, however, does not entirely resolve the overheating problem. For this reason, they have released case fans for Raspberry Pi 4 B. Based on users' tests, the RPi 4's temperature does not go beyond 60°C when there's a fan installed, way below the throttling point of 80°C. The fan thus helps in fully optimizing the Pi's performance while keeping components in average temperatures.
Do you need to purchase a fan when you buy an RPi 4 B? That would totally depend on what tasks you regularly perform with the Pi and how long you're usually using it.
Suppose you're using your Raspberry Pi computer for everyday tasks like web browsing, document processing, playing your favorite music, and other light computing tasks. In that case, you can use the RPi 4 without a fan. If you're just connecting one monitor instead of two, and you're not using it for long periods, then the Pi's temperature would not reach the threshold temperature for thermal throttling. Even if you're not using the Pi intensively, it is still recommended to have a cooling component installed. A heatsink would generally be enough for lightweight tasks.
On the other hand, if you're constantly watching videos, streaming movies, running heavy-computing applications, playing games, and other intensive tasks, installing a fan would improve the Pi's performance and save the Pi's lifespan. Additionally, if you're running dual displays and entirely using all the I/O ports on the Pi, then a fan is more than necessary. You will need a fan if you're regularly using the Pi for more extended periods.
Regardless of what tasks you perform with the Raspberry Pi 4 or for how long you're usually using it; it is still best to install a fan considering the tiny board's upgraded specs. A heatsink may be enough in some cases, but a heatsink and fan combo can better ventilate the CPU and other Pi components.
Raspberry Pi 4 B has the best specs among all the other Raspberry Pi's, but it's also the only Raspberry Pi board with overheating severe problems. Although lightweight computing tasks do not cause the Pi's temperature to go over the threshold, other factors such as too many peripherals connected and prolonged usage can still cause the board to overheat. Updating the firmware and installing a heatsink can somehow alleviate the heat, but they may not be enough to keep the heat dissipated if the Pi is in extensive use. Installing a fan is still the best solution to RPi 4's overheating problems. A fan will maintain the board's performance and keep the components from collapsing, especially the CPU and GPU.
Sources:
[1] Geerling, Jeff, “The Raspberry Pi 4 needs a fan, here's why and how you can add one”, https://www.jeffgeerling.com/blog/2019/raspberry-pi-4-needs-fan-heres-why-and-how-you-can-add-one, July 17, 2019.
