Apple's iPhone Duo moves heat through its hinge with a flexible graphite pipe
Apple's folding iPhone Duo uses a flexible graphite pipe in its hinge to transfer heat between halves, PCMag reports.
The A20 Pro powers the iPhone 18 Pro, iPhone 18 Pro Max, and iPhone Duo. It is Apple's first iPhone chip built on a 2-nanometer process, following the technology's debut with the M6 chip in the Mac mini in August, PCMag reported.
The iPhone Duo's version of the A20 Pro differs from the chip in the other two phones. Murray told PCMag that Apple added a second display engine to support simultaneous operation of the inner and outer displays. He said the increased CPU and GPU performance is intended to deliver a smooth user experience across the displays, and that the inner display also supports placing the FaceTime camera behind the display.
PCMag's report focused on how Apple is managing heat in the new phones. It described a vapor chamber and a material Apple calls "metal over foam." Barabadi said the material "basically creates a direct thermal and mechanically compliant coupling between the SoC and the vapor chamber." She said it is effective at removing heat while meeting mechanical requirements, and that it took months of development to get the material properties right. iFixit also examined the material during its recent teardown of the iPhone 18 Pro, according to the report.
The hinge design presented a particular challenge for the folding iPhone Duo, which doubles in thickness when folded. Barabadi said the thermal issue was "one of the most technically challenging aspects of our design." To address it, Apple routed a flexible graphite pipe through the hinge itself to transfer heat between the two halves, increasing the surface area available for heat dissipation. Barabadi said the part needed to be co-engineered by Apple's thermal and mechanical teams. She described it as a flexible material that must survive many hinge cycles while maintaining both its thermal connectivity and structural integrity over the product life cycle.
PCMag's interview also covered the A20 Pro's architecture, including the benefits of placing DRAM next to the processor rather than stacking it on top. The full interview is available from PCMag.