Innovative Thermal Design
The iPhone Duo is arguably the most exciting iPhone Apple has released for a long time, but there are still some secrets that Apple hasn't divulged about its first foldable — one of them has just been revealed in a recent interview.
Apple executives discussed the development of the A20 Pro chip, confirming that the foldable comes with some unique hardware to better take advantage of the processor's performance power.
The A20 Pro was specifically designed for all three new iPhones, the iPhone 18 Pro, iPhone 18 Pro Max and iPhone Duo. But because the Duo is foldable, things had to change. One such feature is the addition of a second display engine, which allows for simultaneous operation of the inner and outer displays, alongside extra support for the under-display camera.
Graphite Pipe and Vapor Chamber
The most interesting design choice is how Apple handles the issue of heat on the iPhone Duo. The device includes a vapor chamber, which is something competing models like the Samsung Galaxy Z Fold 8 lack. However, managing heat is more complex in a device that changes thickness.
For that reason, Apple also added a flexible graphite pipe through the hinge, to help transfer heat between both halves of the iPhone Duo, effectively doubling the amount of surface area available for heat dissipation.
Apple added a "flexible graphite pipe" through the hinge, to help transfer heat between both halves of the iPhone Duo.
The component was co-engineered with Apple's thermal team, with the express goal of ensuring that a flexible material will be able to survive many hinge cycles without compromising its conductivity or structural integrity.
Like the iPhone 18 Pro and Pro Max, the iPhone Duo also features a direct connection between the A20 Pro and vapor chamber, which ensures better heat dissipation. This connection is made with metal over foam, offering a direct path for heat to travel from the chip to the vapor chamber rather than building up in a single area.
Advantages Over Competitors
Thermal testing on devices like the Samsung Galaxy Z Fold 8 Ultra during graphics benchmarking sessions reveals that heat is often contained within one half of the phone, with very little temperature change across the hinge.
Concentrating heat to that extent can negatively impact sustained performance and cause long-term hardware wear. By ensuring heat can easily cross the hinge, Apple aims to prevent these issues from affecting the Duo.
The effectiveness of these design choices will become clear as the device reaches consumers, with pre-orders scheduled to open this Friday, October 16, ahead of release a week later on October 23.
