Apple routed a graphite pipe through the iPhone Duo's hinge to dissipate heat

Apple built the A20 Pro to deliver laptop-class compute in both the slab-style iPhone 18 Pro and its first foldable, the iPhone Duo, and overcame tight thermal constraints with architectural and mechanical changes. Instead of the traditional package-on-package (POP) stacking that puts DRAM on top of the SoC and traps heat, the A20 Pro uses an M-class-inspired layout that places memory beside the processor. That side-by-side packaging improves data flow and gives engineers more surface area and pathways to extract heat, enabling higher sustained performance for demanding tasks like on-device AI and advanced computational photography.

For the foldable Duo, engineers added a novel mechanical cooling path: a graphite thermal pipe routed through the hinge to move heat out of the limited internal cavity and spread it across the device’s structure. Combining the new chip packaging with hinge-directed graphite cooling lets the A20 Pro run hotter and faster without overheating the phone, while preserving the thin, foldable form factor. The design reflects careful trade-offs between space, thermal management, and sustained performance, positioning the Duo to hit its Oct. 23 release with laptop-level capabilities in a foldable chassis.