TL;DR summary:
- I upgraded from 14 Pro to 15 Pro because I needed greater storage capacity and USB 3 interface
- Moving to 15 Pro affords some quality-of-life improvements
- Make sure external devices don’t draw more than 4.5W
- My iPhone-SSD transfer works at USB 2.0 speed for reasons unknown
(Now the wall of text…)
I might be an unusual case of upgrading from an iPhone 14 Pro to an iPhone 15 Pro. The main reasons for my upgrades are:
- The need for more built-in storage, from 256GB to 512GB
- USB C simplifying my photography and file management workflow while traveling
For context, I will be trekking in Nepal for a month and the iPhone will be my only computer during the period. I am not counting on WiFi connection to work reliably, and I need to be self-sufficient in charging needs for up to five days at a time. The iPhone will serve as the hub which I offload the photos from my camera, and have duplicates saved in an external SSD. In addition, I will record some videos with the iPhone, and it will work with the inReach Mini for satellite communication, routing and logging tracks.
There had been some pleasant surprises:
- The 15 Pro feels lighter than the 14 Pro, and somewhat smaller too. The latter is probably due to the more rounded edges which is easier to hold, besides the weight and (very slight) size reduction.
- The weight reduction makes the 15 Pro stays properly atop my MacBook Pro lid when serving as a webcam, using the Belkin iPhone Mount with MagSafe. The 14 Pro usually tilts slightly to one side because of the weight; I did not remove the phone case as recommended.
- While the 15 Pro performance is 10-20% better than 14 Pro, the 15 Pro is noticeably snappier - apps launch faster, the camera is more responsive, and scrolling is even smoother than the already good 14 Pro.
- I have now acquired the muscle memory of launching the Camera app using the Action button. I am able to keep the iPhone much more stable by having the Action button face downwards while I press it with my thumb, rather than having the button face upwards and I press it with my index finger.
Some observations about the USB C port:
- The iPhone 15 Pro uses USB 3.2 Gen 2 at 10Gbps (~1.25GB/s), as mentioned by @glennf.
- Apple specifies that an SSD with maximum power draw of 4.5W is required for recording 4K60 videos.
- Some SSDs draw more power than 4.5W. For example, the SanDisk Extreme Pro SSD draws up to 7.3W. When I plugged it in, the iPhone initially recognised the SSD, but dropped it and the Files app froze as soon as I started copying files to it.
- Consequently, a powered USB C hub is required when connecting to devices with higher power draw.
- I also tested file transfer with a Samsung T7 Shield 1TB formatted in APFS. This drive works with 15 Pro, since it draws up to 4.1W - within the 4.5W limit.
- It is strange that iPhone-T7 transfer works at USB 2.0 speed (~53 MB/s), while T7-iPhone transfer works at USB 3.2 Gen 2 speed (>650 MB/s). The results are the same regardless of whether TB4 or USB 3 cable is used. The transfers worked at full speed with my Mac. I appreciate your suggestions and comments.
Overall, I concur with the general recommendation that the improvements are mostly incremental; unless some features unique to the 15 Pro (e.g. USB 3.0, recording 4K60 ProRes video) are deemed critical, the improvements over 14 Pro are mostly quality-of-life improvements.