There are not a lot of physical differences between the Series 4 and 5, so it was an easy decision to switch the Series manufacturing equipment over to making Series 5 watches. There are differences, and here is my list:
Apple Watch Series 5 vs 4
- Always on Display using a variable rate refresh that can go down to 1 second intervals (A low-temperature polycrystalline oxide (LTPO) display is a special kind of backplane technology designed for OLED screens and developed by Apple).
- Compass (of course your iPhone has a compass too).
- Cellular Apple Watch has emergency calling when away from your cellular provider (international travel), or if you do not have a cellular contract for your Apple Watch.
- 32GB storage vs 16GB
- Titanium and Ceramic cases available
- S5 CPU on a Chip vs the S4 CPU
- Series 4 is no longer manufactured, and new in the box comes with watchOS 5 vs the Series 5 comes with watchOS 6 and requires an iPhone 6s, SE, 7 or newer running iOS 13.