Frore, the company that developed AirJet ultrasonic coolers, continues to experiment with options for their use. The manufacturer is now testing the use of the AirJet cooler and in particular its more compact variant AirJet Mini in laptops with passive cooling, i.e. where the use of conventional air cooling systems with fans is not initially planned. One candidate for this role was the 15-inch MacBook Air based on the Apple M2 processor.
Previously, OWC, which released storage devices based on NVMe drives with AirJet cooling systems, as well as Zotac, which released a compact Nettop with a similar cooler, were interested in Frore’s developments. But they haven’t appeared on laptops yet.
AirJet is a compact rectangular unit that is installed on a processor, chipset or other heating element. The air flow is used for cooling. It is pumped not by rotating fan blades, but by copper membranes that vibrate at ultrasonic frequencies. The technology is based on the jet flow effect known from aviation, which is used to cool jet engines. Air is drawn in through slots on the top of the AirJet unit, directed to hot system components, absorbs heat from them, and is released through vents in the laptop case. The AirJet is only 2.8 mm thick. This is almost half the thickness of typical laptop fans, which is 5mm.
Journalists from The Verge who visited the company’s testing laboratory talked about the progress of Frore’s new experiment. According to the company’s engineers, the 15-inch MacBook Air based on the Apple M2 processor was a suitable environment for evaluating the effectiveness of the AirJet Mini cooler for one simple reason: this laptop is not equipped with an active cooling system. At the same time, it is one of the thinnest mainstream laptops on the market – its thickness is only 11.5 mm.
The specific design of the 15-inch MacBook Air does not require any changes to the cooling system. In order to integrate even a cooling system as thin as the AirJet Mini, Frore engineers had to reduce the thickness of the back of the laptop by 0.3 mm through milling. In addition, as part of the experiment alone, a speaker and a WiFi antenna had to be removed from the laptop.
At the same time, Frore integrated not just one, but three AirJet mini coolers into the laptop, united by a common cooler. According to the company, each AirJet Mini is capable of dissipating 4.25W of thermal energy. The cooler developer also says that AirJet will enable the production of even thinner laptops in the future, with a thickness of 9.5 mm. However, for this it is necessary that the development of such laptops was initially carried out taking into account the use of similar coolers in their designs, which, of course, was not provided for in the case of the MacBook Air 15.
Each individual AirJet Mini Cooler only consumes 1 watt when running and 0.1 or 0.2 watts when idle. However, The Verge’s journalists found that the three AirJet Minis included in the MacBook Air 15 together consume just over 5W of power through the USB-C port on the laptop itself. According to Frore, the AirJet Mini’s cooling system operates 10 to 15 percent of the time during average laptop use.
In practice it became clear that the longer the AirJet runs, the more obvious its advantages over the original passive cooling system of the MacBook Air 15 become. Even in the first tests in the Cinebench R23 benchmark and in the game Shadow of the Tomb Raider, the performance of the laptop with this The cooler was slightly higher than on a MacBook Air without it. In the game with a cooler, the laptop showed 29 FPS, and without – 28 FPS. The Xcode benchmark was completed in 172.7 seconds with the AirJet cooler and 178.2 seconds without it.
After about half an hour in the Shadow of the Tomb Raider gaming test, the frame rate of the standard MacBook Air 15 dropped to 22 FPS, and the modified version with AirJet showed a frequency of 27 frames per second. After 40 minutes of play testing, the Mac without AirJet experienced significant image stuttering. The AirJet variant continued to show acceptable performance.
In Cinebench R23, after several runs, the multi-threaded performance of the MacBook Air 15 with AirJet was 8775 points and without AirJet 8380. According to the monitoring data provided, the system could not maintain a consistently high CPU frequency without a cooler. As the frequency increased, the power consumption of the M2 processor also decreased – simply because this is the only way to cool the CPU in a laptop without an active cooling system. According to Frore, the M2 processor in the MacBook Air 15 can run at 3.2 GHz, but after 30 minutes of the Cinebench R23 benchmark, it automatically throttled to 2.8 GHz.
Journalists from The Verge also confirmed that AirJet is significantly quieter than a traditional blade cooler. Additionally, its efficiency is on par with a traditional fan in a typical laptop cooling system. At the same time, this doesn’t convince us that AirJet coolers can completely displace traditional air cooling systems from mobile laptops. Rather, with such coolers you can save space in the interior, for example to install larger batteries without increasing the thickness of the laptop.