IT Home, October 13: Tech media PCMag published a blog post yesterday (October 12), interviewing two Apple executives who revealed for the first time the hinge cooling solution for Apple’s first foldable smartphone, the iPhone Duo.
Apple’s VP of Chip Engineering, Dan Murray, and Senior Manager of Thermal Product Design, Banafsheh Barabadi, provided detailed insights into Apple’s custom thermal solutions during an interview with the outlet, maximizing the sustained performance output of the A20 Pro chip in the iPhone 18 Pro, iPhone 18 Pro, and iPhone Duo.
Regarding the A20 Pro packaging, the chip uses a wafer-level multi-chip module (WMCM) package that relocates the DRAM from above the processor to the side. According to a blog post cited by IT Home, Apple states that this design creates a direct thermal path from the chip to the heat spreader, eliminating the thermal bottleneck present in the previous package-on-package (POP) solution.
In the iPhone 18 Pro and Pro Max, the vapor chamber has three times the surface area of the iPhone 17 Pro and contains more deionized water. The vapor chamber also serves as a structural frame, with the battery and logic board directly mounted on it, using 80% recycled stainless steel.
Apple also uses a nanotwinned copper metal plate on the back of the display, layered with high-thermal-conductivity graphite. Together, these materials enhance lateral heat dissipation across the screen, reduce hotspots, and meet the mechanical strength requirements of the display.
The iPhone Duo uses a thinner heat pipe than the iPhone 18 Pro, suspended in the middle of the chassis. Since the device's thickness doubles when folded, Apple connects the cooling structures on both sides with a flexible graphite tube inside the hinge.
Flexible graphite tubes are flexible thermal conductive components made from graphite material that can be bent and arranged within limited spaces. They transfer heat from heat-generating areas to other regions and are commonly used for thermal management in compact electronic devices such as smartphones and laptops.
Apple states that the new cooling system supports workloads such as gaming, video recording, and on-device AI, with the iPhone 18 Pro delivering a 35% improvement in sustained GPU performance over the iPhone 17 Pro; the A20 Pro offers a 20% increase in CPU performance and a 40% increase in graphics performance.