Apple’s new iPhone 17 lineup hides a performance compromise that many buyers won’t notice until they dig deeper. All 256GB models across the series, including the iPhone 17, 17 Pro, and 17 Pro Max, ship with significantly slower flash storage than their higher-capacity counterparts. And here’s the catch: upgrading storage later doesn’t solve the problem.
Storage Speed Split in the iPhone 17 Series
Tests show a clear divide between storage speeds depending on the model. The 256GB versions of the iPhone 17 lineup achieve AnTuTu storage scores of around 90,000 to 100,000 points. In contrast, the 512GB and 1TB versions deliver roughly 150,000 points. While the 2TB Pro Max hasn’t been benchmarked yet, it’s expected to use the same high-speed memory.
The surprise is the iPhone Air. Every model, regardless of storage size, uses high-speed flash memory and features several new technologies. It’s a rare move from Apple, suggesting that the Air is meant to stand apart as a more balanced device.
Credits: DirectorFeng
Tech reviewer DirectorFeng highlighted this shift in a detailed post, revealing that Apple no longer treats storage upgrades the same way. In past iPhone models, jumping from a lower to a higher storage variant usually restored full read and write performance. That’s no longer the case. If you buy a 256GB iPhone 17 and later upgrade it to 512GB or even 1TB, the read and write speeds remain at the slower level.
How it affects buyers
The numbers might not sound dramatic on paper, and in everyday use, most people won’t notice much difference. Apps still launch quickly, photos save instantly, and typical tasks feel smooth. But there’s a real impact in scenarios that demand sustained high-speed performance:
Video production : Recording and transferring RAW or ProRes footage takes longer.
: Recording and transferring RAW or ProRes footage takes longer. File handling : Offloading large files over a wired connection becomes slower.
: Offloading large files over a wired connection becomes slower. Future upgrades: Custom storage upgrades won’t deliver the speed you’d expect.
The issue goes deeper. Apple ships 512GB and higher-capacity models with their motherboard set to “high-speed mode,” while the 256GB versions run in “low-speed mode.” Changing that requires replacing the motherboard, which is expensive and undermines the point of a storage upgrade.
iPhone Air: The Unexpected Standout
While the 256GB iPhone 17 models disappoint in this department, the iPhone Air bucks the trend. All variants use high-speed flash memory, suggesting Apple is positioning the Air as more than a budget-friendly alternative.
If DirectorFeng’s upcoming tests confirm that the Air’s flash memory can be installed into the Pro models to improve performance, it would indicate compatibility between the two storage types but that remains theoretical for now.
For users planning to upgrade their iPhone 17 storage later, this development is a warning. The hardware difference means a 512GB upgrade won’t match the speed of a factory-shipped 512GB model. At present, only the 256GB versions of the 17 Pro and 17 Pro Max can be expanded to 1TB using slower flash memory.
So, In short
Apple’s decision to use slower flash memory in 256GB models raises questions about how much performance buyers are getting for their money. The company has created a clear gap between base and higher-tier models, and that gap doesn’t close even if you pay for more storage later.
For most people, the slowdown won’t affect daily use. But if you care about transfer speeds, professional workflows, or futureproofing, you should avoid the 256GB variants and start with 512GB or higher. And if you want consistent performance across all capacities, the iPhone Air might be the more interesting choice this year.