iPhone Duo Fold Testing Reveals What Samsung Already Knew
CNET's custom folding rig is putting Apple's first foldable through its paces—and early results suggest the device may struggle where Samsung spent seven years perfecting its hinge. Here's what the data could mean for the foldable market.
Apple’s First Foldable Is Already Showing Cracks
CNET has something rare: a purpose-built machine called Fold-a-Phone, designed to open and close foldable phones on a continuous four-second cycle until one of them breaks. The iPhone Duo is now strapped into it. Samsung’s Galaxy Z Fold 8 is already there too, having been tested before Apple’s entry even shipped.
The implications of that head start are exactly what they sound like.
Seven years is a long time in consumer hardware. Samsung launched its first Galaxy Fold in the United States in September 2019. Motorola was experimenting with trifold designs that same year. Apple’s iPhone Duo arrived in stores in Louisville, Kentucky on a Friday afternoon after a three-hour wait—now it’s being subjected to the same brutal, repetitive stress that Samsung’s engineering teams have refined across generations of foldables.
How the Test Actually Works
The Fold-a-Phone isn’t a speed demon. That’s the point. The machine opens the phone in one second, lets it fully extend for another second, closes it over one second, and holds it shut for one more. Each complete cycle takes four seconds—roughly how fast a person actually uses a foldable in a real day.
Test it any faster and you generate excess heat and stress the hinge artificially. Test it too slowly and you waste the lab’s time without adding resolution. The team settled on the cadence deliberately.
An industrial stepper motor drives each armature, with software monitoring torque in real time. If proximity sensors detect misalignment, the machine stops immediately. Power draw is logged continuously. Cameras capture the phone from multiple angles throughout the test. Everything is backed up to multiple locations and powered through an EcoFlow Delta 3 Plus so an outage never ends a test early.
Each phone mounts to a custom sled—3D-printed on a Prusa Core One to match the device’s exact dimensions—secured with heavy-duty double-sided tape and bolted to the machine.
It’s a setup built for data, not drama.
What the Numbers Already Mean
Most foldables on the market today carry ratings between 200,000 and 500,000 folds. A phone that gets opened and closed dozens of times a day would theoretically last between four and fourteen years under that rating. But those are manufacturer claims, not independent measurements.
Apple hasn’t publicly disclosed any fold lifespan specification for the iPhone Duo. That absence matters. It forces every analyst and buyer to rely on third-party testing—and CNET’s rig is now producing that data in real time.
The Z Fold 8 has been on the machine longer. Samsung knows its hinge tolerances. It knows where the first sign of wear appears and at what cycle count. Apple is still mapping its own device’s breaking point.
That gap is structural, not accidental. Samsung entered this category when foldable screens were essentially a laboratory curiosity. Its engineers have had seven years of failure data, supplier relationships, and iteration cycles accumulated across five generations of foldable handsets. Apple entered as a newcomer with a single product attempt.
Who Wins and Who Loses
Apple wins if the iPhone Duo simply works well enough to legitimize the form factor for mainstream buyers. Its brand pull alone compresses the timeline for foldable adoption across the industry. The device’s existence changes the conversation regardless of hinge cycles.
Samsung wins if the iPhone Duo fails or struggles early in testing. Every reported fold-count number that falls below Samsung’s benchmarks reinforces the narrative that Apple is behind—which it objectively is. Samsung’s market position depends on foldables remaining a premium category where experience and iteration matter more than brand prestige.
Consumers win either way, but the timing differs. If Apple’s first attempt proves durable, it drags the entire market forward faster with price competition and feature improvements. If it doesn’t, buyers face a longer wait before foldables become reliable everyday devices rather than expensive curiosities.
The Livestream Factor
CNET is broadcasting the testing live on YouTube Monday from 1 to 5 p.m. ET. That format itself signals how much attention this moment carries. People want to watch a $2,000 phone get folded to death in real time.
This is the first time a major tech outlet has subjected Apple’s first foldable to public, systematic stress testing. The data coming out of it will circulate widely and be referenced constantly in reviews, comparisons, and purchase decisions for the foreseeable future.
What Happens Next
The Fold-a-Phone will keep running. CNET has committed to ongoing status updates and comparisons between the Duo and the Z Fold 8 as testing continues. The methodology is transparent enough that other outlets can replicate it. Apple’s hinge will reveal its limits eventually—either at 100,000 cycles or 400,000, the number will land somewhere and the market will react accordingly.
For Samsung, the test machine is a reminder that its advantage isn’t permanent. Seven years of lead can erode quickly if the next generation of iPhones delivers a sufficiently refined first impression. For Apple, the machine is both a liability and a mirror: it will expose weaknesses, but surviving it would make the Duo credible in a way no marketing campaign ever could.
The hinge doesn’t lie.
Matthew Murray oversees CNET’s lab operations and has spent sixteen years in hardware testing across PCMag, Future plc, and other tech outlets. His team built the Fold-a-Phone specifically for this moment.
The iPhone Duo is still folding.