iPhone 17 Pro Max iPhone 17 Pro Max USB 3 very slow via Sync

[bytefusion]

Hello,

the iPhone 17 Pro Max is very slow when syncing or transferring files. This is despite Apple promoting USB 3 support since the iPhone 15 Pro series.
The transfer speeds are extremely slow only around 50 MB/s to 70 MB/s.
This is the case when transferring files through Finder and during the AppleMobileBackup process (the iOS backup process in macOS).

1) Setup:
- MacBook Pro M1 (Thunderbolt 4 port) - macOS 26.0
- Apple Thunderbolt 4 and Thunderbolt 5 cable
- iPhone 17 Pro Max (USB 3 support) - iOS 26.0

2) Test Procedure:

I transferred a 5 GB video file using Finder -> Files

I also performed an backup via the AppleMobileBackup process, which involves syncing over USB.

3)
Test Results:

File Transfer Speed: 50 MB/s to 70 MB/s

Backup Size: More than 100 GB

I used an open-source tool (Stats) to monitor the transfer speed and confirmed these low speeds.

 

[abemonkey]

I just noticed the same thing. Using a Samsung external SSD USB 3.0 drive. It was WAY faster on the iPhone 16 pro max. I'm on the 17 pro max with 2TB. Very sad.

 

[jbrwTP7u]

I got the OWC TB5 cable today, I also have the Anker TB4. The only good speeds I got were during DFU restoring iOS. It was around 500 MB per second according to Activity Monitor, which is about 4 Gbps. Still not 10 Gbps, but manageable. Backup and restore stayed constantly around 90 to 100 MB per second, which is way slower than 10 Gbps, more like 1 Gbps. Shame. This was disappointing on the iPhone 15 Pro Max, and now the disappointment continues.


This would have been acceptable in the iPhone 6 era with 32 GB of storage, but with 512 GB and larger phones it is a major pain in the ass. Also, iCloud backup sucks balls.

 

[menist]

The included USB-C cable in the box is still USB 2.0 speeds. You need a new cable that's USB 3.2 compatible. I'm having zero issues with transfers on the 17 Pro. 80GB backup/transfer and 20GB music library was sync pretty quick.

 

[jbrwTP7u]

The included USB-C cable in the box is still USB 2.0 speeds. You need a new cable that's USB 3.2 compatible. I'm having zero issues with transfers on the 17 Pro. 80GB backup/transfer and 20GB music library was sync pretty quick.

Who said I’m using that cable? I have Thunderbolt 4 and Thunderbolt 5 cables, short & thick ones from Anker and OWC.

 

[bytefusion]

The included USB-C cable in the box is still USB 2.0 speeds. You need a new cable that's USB 3.2 compatible. I'm having zero issues with transfers on the 17 Pro. 80GB backup/transfer and 20GB music library was sync pretty quick.

Quick is relative.
If you’ve only ever used included USB-C USB 2.0 cables (real-world ~35-40 MB/s), then yeah, 90-100 MB/s feels blazing fast and "pretty quick".
But the iPhone 17 Pro actually has USB 3.2 Gen 2 hardware capable of 10 Gbit/s (~1.25 GB/s theoretical, >800 MB/s easily achievable in practice).
With a proper USB-3.2 Gen 2 or Thunderbolt 4/5 cable you’re looking at 700–900 MB/s sustained on large files.

80 GB backup/transfer at 100 MB/s = ~13–14 minutes

80 GB backup/transfer at 800 MB/s = under 2 minutes

Just the 20 GB music library:
100 MB/s → ~3.5 minutes
800 MB/s → under 25 seconds